Primary Powerset: Dual Pistols
Medium+ Single-Target Damage*, Medium+ Area of Effect (AoE) Damage* (2 Cones, 1 Targeted, 1 PBAoE), Medium Control**, Medium Debuff Potential**
*Ammunition powers will add variance and Dual Pistols has many proc options which also push damage higher.
**Ammunition powers introduce options for controls such as Hold or Knockdown as well as various debuff options.
Dual Pistols is a unique blast set which was added during the Going Rogue expansion and was released alongside Issue 18. Dual Pistols features some incredibly over the top gun fu inspired by Hong Kong action films. Perhaps one of the most notable sources of inspiration stems from the 2002 cult classic film Equilibrium. What makes Dual Pistols so unique from other blast sets is that it includes neither a snipe nor Aim. Alternatively, Dual Pistols features an ammunition swap mechanic in place of Aim and Executioner's Shot in the place of a snipe. The level 26 power, Piercing Rounds, is a unique cone with the "Narrow" quality giving it an area of effect more like a line. Beam Rifle, introduced in Issue 21, is the only other set with a similar cone.
Dual Pistols is often criticized for its low to mid tier damage and the powers it lacks (e.g., Aim). However, the way Dual Pistols is designed makes its effectiveness deceptive. In practice, Dual Pistols is a better set than it often gets credit for. Dual Pistols is a fantastic support set with decent damage output. All Dual Pistols powers have some secondary effect (sometimes several) which is improved by archetype modifiers. Defenders have the highest of these values with Sentinels having the lowest of these values. Sentinels can still contribute as minor support despite this if they so choose.
The strength of Dual Pistols is its versatility. This versatility can change how you use the set in various team compositions. Invention Origin (IO) sets also open up a lot of build opportunity to close its damage dealing gaps.
Beginner's Overview
So, if my fantasy of being Mark Lee (A Better Tomorrow, 1986), John Preston (Equilibrium, 2002), Wesley Gibson (Wanted, 2008), or John Wick (John Wick, 2014) isn't met with WTFBBQ levels of damage then what gives?
Dual Pistols has several quick animating and recharging powers. The speed of these powers comes with lower damage per hit, but this doesn't mean the powers are weak. A nice feature of Dual Pistols, at least for Sentinels, is that most of the powers are relatively competitive with one another in various circumstances and conditions. This means you can choose powers you want and ultimately build around your choices. Not many power sets offer that when discussing optimization options.
As noted before, the powers for dealing damage offer a lot of options and flexibility. On top of that, Dual Pistols gain access to Swap Ammo. This power is your Aim replacement and it grants you the ability to change how you play. This gameplay swapping can change the effects of your powers to either grant additional damage or change the fundamental debuff associated with various effects. Below is an overview of how the ammunition system works.
Swap Ammo:
About 70% of every Dual Pistol attack is Lethal damage. The other 30% of the damage depends on which of the 4 ammunition types are currently active. The default ammunition is "Standard" which is also Lethal (so 100% Lethal by default). Each power also carries with it some form of secondary effect. These secondary effects are replaced based on the ammunition type being used. Below is a list of each power's effect under Standard Ammunition. Suppressive Fire is an exception to this design. Suppressive Fire splits its damage 50/50 between lethal and elemental types.
Power
Secondary Effect
Pistols
Defense Debuff
Dual Wield
Chance to Knockback
Empty Clips
Chance to Knockback, Defense Debuff
Suppressive Fire
Stun
Bullet Rain
Chance to Knockback
Executioner’s Shot
Chance to Knockback, Defense Debuff
Piercing Rounds
Resistance Debuff
Hail of Bullets
Chance to Knockdown*
*During Standard Ammunition the chance to knockdown at the end of the animation is guaranteed but moves down to "chance to knockdown" with other ammo types.
Swap Ammo grants 3 toggle powers which cost no endurance to run. If no toggle is active, then the default Standard Ammunition is used.
Chemical Ammunition converts the secondary damage from Lethal to Toxic. All secondary effects are replaced with a damage debuff except for Suppressive Fire which is changed to a Hold effect.
Cryo Ammunition converts the secondary damage from Lethal to Cold. All secondary effects are replaced with a slow (both attack rate and move speed) except for Suppressive Fire which is changed to a Hold effect. Special: The Sentinel version of this power grants a 33% bonus to power range. Turning this power on does add a buff that can be viewed in the Combat Attributes and it will improve the range of your powers. The exact text of the effect in the power description states it ignores buffs and enhancements. So while my Combat Attributes shows me a total of 53% range bonus due to the two ATO's the real effect does seem to ignore that. So the range addition isn't particularly great, but it also seems to effect the cone width on Empty Clips (and like Piercing Rounds but currently not using it). So this effect brings some additional utility for creative players to tinker with. Thanks to @Riverdusk for pointing it out and encouraging further testing.
Incendiary Ammunition converts the secondary damage from Lethal to Fire. All secondary effects are replaced with a short duration fire-based damage-over-time (DoT) except for Suppressive Fire which is changed to a Hold effect.
Dual Pistols has a host of options. Chemical Ammunition's -damage debuff may not be much, but it can contribute to damage mitigation for the Sentinel as well as teammates. Slow effects and knockdown/knockback are good ways to allow regeneration effects to heal the Sentinel. Even if these effects don't do much by themselves they do interact with other archetypes to magnify them. Experiment! Explore!
Slotting
Basic Slotting
Dual Pistols is a set with higher than normal innate accuracy. This partially makes up for not having Aim and can let many players get away with running 1 accuracy enhancement. There are also 3 powers that can reduce defense with Standard Ammunition which should help reduce misses in the lower levels. Most of the attacks in Dual Pistols recharge and animate rather quickly and it will create a significant drag on your endurance. I recommend at least 1 endurance reduction in your attacks. The amount of recharge reduction is going to depend based on how many attacks you have selected. If you're taking everything in order to explore the set, then you should have at least one power available. I wouldn't recommend enhancing damage beyond 3 Single Origin (SO) or basic Invention Origin (IO). The diminishing returns on enhancements isn't worth pursuing. This may leave 1 slot open if you are fully enhancing a power(s). You could further enhance recharge or endurance modification. You may also wish to enhance some of the secondary effects like defense debuffs. Keep in mind that defense debuffs are linked to Standard Ammunition and those enhancements will offer no benefits with other ammunition types.
Advanced Slotting
Dual Pistols is a set that is wide open for creative build possibilities. Realizing this potential can also be closely linked to your secondary power set. What this means is that some secondary sets may demand more defense potential from IO sets found within the Ranged Attack category (e.g., Thunderstrike). If your Dual Pistols is paired with a resistance-based secondary, then you may want to consider the more defensive-based sets. If your Dual Pistols is paired with a defense-based secondary (e.g., Super Reflexes), then your attacks should be enhanced to maximize their damage output. Maximizing your damage output under this context is about using damage procs (e.g., Explosive Strikes (Knockback Set): Chance for Smashing Damage).
While there are a number of options to chose from, a Sentinel is primarily a damage dealing archetype and gains more out of damage enhancement over enhancing secondary benefits (e.g., Defense Debuff, Hold Duration, etc.). I did mention that players should feel free to explore though. So you should make careful consideration about the ramifications on fully enhancing a primarily damage dealing power with something that is not directly related to damage. If doing something like this works for you and your teammates, then go for it. However, for most players this is not an optimal path to take.
Pistols - This can take a number of sets from the Ranged Attack, Defense Debuff, and Accurate Defense Debuff categories. Ideally, you want a damage set here to enhance the primary function of the Sentinel. However, you can accomplish this in a number of ways. If you are running a resistance set (e.g., Radiation Armor) then look for sets that grant you some defense or recharge. Thunderstrike is a good one for defense and Decimation is good for recharge. If your defense is already covered by a secondary (e.g., Super Reflexes), then you have several options. You can keep to running a complete or nearly complete set (5-6pc) or you can explore damage procs. Pistols can accept the Achilles' Heel, Touch of Lady Grey, Shieldbreaker, and Gladiator's Javelin procs.
Dual Wield - General slotting is going to be very similar to Pistols with the exception of which auxiliary sets it can access. Dual Wield cannot access the Defense or Accurate Defense debuff category but it can access the Knockdown and Slow categories. Sets of note include the Impeded Swiftness, Explosive Strikes, and Force Feedback for their available procs. Force Feedback is a possible way to "cheat" in extra global recharge reduction to a build and several powers can take this.
Empty Clips - This power accepts the Targeted Ranged Attack, Knockback, Slow and Defense Debuff categories. Ideally, you will want to maximize the damage potential but there are some very good procs that work in this power. Sudden Acceleration's Knockback to Knockdown makes for a welcome change in groups. Force Feedback's Chance for Recharge has a chance to trigger per target hit. This power can also accept Achilles' Heel's resistance debuff as well as several damage procs. I recommend players stick to something that primarily benefits damage up to 5 slots, but a 6th slot is a good reserve for some form of proc. Ideally that proc is utility-based like Force Feedback or Achilles' Heel.
Suppressive Fire - This power accepts Ranged Attack, Stun and Hold category sets. The Hold category is the real gem here. The Hold category has 4 damage procs available! Damage procs are what makes Suppressive Fire potentially one of, if not the, hardest hitting powers in the set. If you are not a fan of random chance effects, then this power loses a lot of effectiveness. If you're running Standard Ammunition the most, then this power is still one of the strongest damage powers in the set. It is worth enhancing the damage in some form. I would not recommend enhancing the Hold/Disorient duration.
Bullet Rain - Bullet Rain can take sets from the Targeted AoE, Knockback and Slow categories. Ideally, you want to slot this with a similar strategy to Empty Clips which means enhance the damage. However the 6th slot, if you 6 slot it, is just as flexible on utility proc opportunity. If you prefer to run Standard Ammunition, then the Sudden Acceleration Knockback to Knockdown is just as welcome here as it is in Empty Clips. Bullet Rain is an even better carrier for Force Feedback's Chance for Recharge. Bullet Rain has a target cap of 10 targets vs the 6 with Empty Clips. Each target has a chance to trigger a proc which makes Bullet Rain an excellent source to improve the consistency of that recharge effect. Due to how procs work, you cannot guarantee a triggering of the effect, but having 10 rolls of the dice is as good as it gets on the Sentinel.
Executioner's Shot - This power can take everything from the same categories as both Pistols and Dual Wield. Executioner's Shot is the highest DPA power in the set. It is not a great vehicle for adding more secondary effect duration. It is a potentially good candidate for any number of damage procs as well as the very rare sets. If you're enhancing this heavily with a set, then your choices are broad. However, this power is so strong for delivering procs that I find it hard to pass up. If you feel you need Thunderstrikes for your build, then try to do that in all of your other powers before you enhance this one. If you can use a 5pc set, non-Thunderstrike, here and use the 6th slot for a damage proc, then you will get more mileage from it.
Piercing Rounds - This power can take sets from the Targeted AoE and Slow categories. The "Narrow Cone" quality creates a very unique opportunity under the procs per minute (PPM) rules. The cone size is small enough that it doesn't hurt the PPM calculations nearly as much as many other area of effect powers do. This means Piercing Rounds is a good power to accept the Annihilation proc for -resistance. You won't make or break your build with this proc but it is a unique power with a higher probability to activate than most area powers.
Hail of Bullets - This is a Point-Blank Area of Effect (PBAoE) and as such it has several options from some more melee-oriented sets. These types of sets are great sources of additional recharge (Obliteration, Armageddon, etc.) as well as damage proc potential. Hail of Bullets can also take sets from the Knockback category which means this power has a high chance to activate the Force Feedback chance for recharge. Hail of Bullets can also take on the Fury of the Gladiator's resistance debuff with a very high chance to activate it.
What a minute... I didn't mention the Archetype Origin (ATO) enhancements! That's on purpose. The Sentinel ATOs are very utility oriented which makes it difficult to prescribe blanket recommendations on where to put them. In general, both ATOs have good global bonuses, but their special effect procs require some understanding to make use of them. I'll explain what they do below and with that information you can decide where they work best for your character.
Opportunity Strikes - This is a decent set and at 5 pieces you can access the global recharge benefit. The 6th piece is a range defense perk. The other valuable bonus worth noting is the enhanced range global bonus. That's right, the range increase affects all your powers. That means you can initiate combat from slightly greater distances and it will makes your cones wider. The special effect proc from this set is a "Chance for Opportunity". As of Page 5, this proc grants a minor boost to your meter recover (about 10% at Superior quality). This set can be slotted in either Single Target or Area of Effect powers. Which type of power you wish to slot this in is going to be dependent on personal preference. In general, I'm not a huge fan of this effect and often place the entire set in one of the Area powers for maximizing benefit while grouping.
Sentinel's Ward - The Ward set has a similar theme to the bonuses like what Opportunity Strikes grants. You get a defensive bonus at 5 pcs and a recharge bonus at 6. You also have access to another source of range bonus. Either or both of these sets can be split to take advantage of that if you do not care for or need the higher tiered perks. The proc is an absorb shield. For Dual Pistols you can place this anywhere depending on the needs of your build. It is worth noting that due to the higher PPM value this works very well in area powers. Every target has a chance for the absorb shield to trigger turning a power like Bullet Rain into a hybrid of defense and offense.
Skippable Powers
What should I skip is a very common question. The answer to that can be complicated as various powers work better in certain configurations. That said, let's walk through the powers:
Dual Wield vs Pistols: Pistols can potentially out perform Dual Wield when talking about basic damage enhancement slotting. Pistols has a better damage-per-activation, even with the fire damage difference in Dual Wield, and benefits well in builds with extreme recharge. Dual Wield on the other hand, is slightly better at trigger damage procs and has access to a 4th damage proc Pistols does not (2 options out of the Slow category). In addition to the extra damage potential of procs, Dual Wield can also make use of Force Feedback: Chance for Recharge. There is no clear winner here without having a much deeper discussion on where your build is ultimately going to go. That said, Dual Wield will likely edge ahead in most builds attempting to leverage heavy use of procs for damage. Pistols, in the same kind of build consideration, needs more recharge and the total outcome is relatively minor. You have to pick one, and which one you chose is more dependent on what build path you want to take. Both options can be viable under their respective conditions. You only need one of these, and definitely don't need both (there are better options later).
Empty Clips: Some people don't like cones and that's OK. However, Empty Clips has pretty decent DPA for a cone attack making it a competitive choice to both Pistols and Dual Wield in the early game. In essence, this works really well as a gap filler early on even in single target situations (be mindful of the higher end cost though, that can drain your blue bar fast). That said, if you hate cones, then I guess you could skip this.
Swap Ammo: This is your Aim. Not only does the fire ammo type increase your overall damage, but you can swap it around for completely different effects. Some people do not like this system though, and decide to skip. I don't recommend that, but you do you. 😉
Suppressive Fire: This is the only power in the set with a 50/50 split on elemental damage vs mostly lethal damage. While Suppressive Fire doesn't get the fire damage-over-time effect as other powers do, it does get half its damage converted into that element. That alone is pretty significant. Furthermore, this can pull IO set options out of the Hold category which means there are a lot of damage proc options. Suppressive Fire can easily be turned into a high damage power, and therefore I highly recommend taking it. That said, I've seen people skip this so that is an option, I guess.
Bullet Rain: This is your largest non-T9 AoE. Given that the Sentinel lacks the AoE options of other ranged ATs, there is just no compelling argument (outside some roleplay idea) to recommend skipping this. Sure, the homing bullets are ridiculous, but this entire set is in a comic book game. If you're looking for realism you picked the wrong game. Take this.
Executioner's Shot: This is the most efficient damage power for single targets in the entire set. This power only gets better with with its various slotting options and becomes available around the same time as other blast sets getting their snipe. OK look, I know DP doesn't have a snipe anywhere. My point is, ES is effectively the snipe power replacement, and it has always been a strong power choice. I've seen people skip this before across all ATs. I'll never fully understand why people do that and then complain about damage.
Piercing Rounds: So far, my recommendations haven't really planted a firm stake in the ground on when to skip. I mean, pretty much all of the powers in this set are pretty good for damage. So, I guess we have to have one real standout stinker. That stinker would be Piercing Rounds. The biggest selling point of Piercing Rounds I could ever give, is that it includes a fairly hefty resistance debuff when playing anything other than the Sentinel. The Sentinel's version of the same debuff is the weakest of all ATs that get this power. Furthermore, Piercing Rounds has some unique traits in its area of effect, animation time, and recharge which make it strong at delivering procs. HOWEVER, it is *really* slow to animate. The way that Suppressive Fire works in conjunction with Executioner's Shot (and likely either Dual Wield or Pistols) overshadows Piercing Rounds for Sentinels. Piercing Rounds isn't total garbage for Defenders, Corruptors, or Blasters however. Keep in mind both Corruptors and Blasters have a strong damage proc available in one of their ATO sets and it can work surprisingly well in Piercing Rounds. That option doesn't exist on Sentinels. Defenders get a whopping -20% resistance debuff in that power vs the Sentinel's just over 9% version. See where I am going with this? Sentinels inherit all of the weakness of Piercing Rounds but don't have any of the bells or whistles to offset it. Skip it on Sentinels. Consider taking it on any of the other ranged ATs depending on what you want to do with it.
Hail of Bullets: This is your other large (for Sentinels that is) coverage area damage power. The big downside it is melee range, but you do get a defense benefit for a few seconds to compensate. I'd suggest taking it.
So, from the above you could skip either Pistols or Dual Wield, skip Empty Clips (I guess), and skip Piercing Rounds. Other than that, you should strongly consider taking everything else.
Rotations
Post Page 5 changes, this section can be much smaller. When Opportunity used to exist and force a choice in the T1/2 powers there were ways to squeeze out effectiveness that no longer matter (not that it was a big deal then either).
For Sentinels:
There are two primary ways to get the most out of your single target sequence vs a hard target. You want to do either:
A) Dual Wield -> Suppressive Fire -> Executioner's Shot; or
B) Pistols -> Suppressive Fire -> Executioner's Shot.
The exact order doesn't really matter that much. The only thing which may change your decision making is if you use Achille's Heel: Chance for Resistance Debuff in Executioner's Shot. If you have that, then you may want to lead with that power since everything after it will benefit from the resistance debuff (including follow-up Executioner's Shots).
The major difference between the two options above is that in option A is animation time, and that Dual Wield is better for proc damage than Pistols. The first run is the most forgiving sequence on global recharge. Option B really only becomes competitive if we exclude damage procs and/or include extreme amounts of recharge. You'd want Executioner's Shot to recharge in 2.9 seconds in order to avoid using Pistols too much. If you want to use procs in Executioner's Shot, without any recharge in that power, then you're global recharge total needs to be quite high (greater than 200%). This just isn't practical in most builds and would require Ageless Destiny running for a short window of opportunity to really maximize it. So, for the average proc heavy build, go with option A and use Dual Wield. Overall, the animation transitions will likely feel a bit smoother. Other ATs:
Either of the previous options above, and also:
Pistols -> Executioner's Shot -> Pistols -> Piercing Rounds.
Suppressive Fire was changed for all other ATs to provide another damage dealing alternative plus the change came with a slightly faster animation time. So, really any of the ATs essentially have the same basic attack rotation options now. Piercing Rounds was also changed to provide its resistance debuff at all times even if an ammo is active. This does present an opportunity to use the debuff more actively and works very well with Corruptors and Defenders looking for more support gameplay.
Sadly, the debuff amount on Piercing Rounds was not touched for Sentinels. Unfortunately, it is not that great of an option when we have all these damage procs that can be stuffed into other powers like Dual Wield, Suppressive Fire, and Executioner's Shot. That option dramatically raises the damage potential of that combination which overshadows the -9.6% resistance effect in the current Piercing Rounds. However, if procs become neutered this could completely change the dynamic. We can think of this in this way:
Piercing Rounds can be pushed down to 4.224 seconds in recharge. Pistols - Executioner's Shot - Pistols animates in 4.224 seconds. You could have the debuff active by the next use of Piercing Rounds (essentially buffing itself). This cycle runs just over 6.8 seconds.
If you have enough recharge to get Executioner's shot to 2.9 seconds (which is possible), then you could run Executioner's Shot - Pistols - Suppressive Fire - Executioner's Shot. That runs about 6.6 seconds.
Without any procs, these two options are pretty competitive (at least when the damage resistance works in your favor), but due to current slotting options Piercing Rounds just falls short of other possibilities.
About Ancillary/Patron Pools:
There is a lot to unpack by adding in more complexity with the higher level pools. I'm not going to go into all of the variations possible. There just isn't enough space and there is just too much to go over. Furthermore, discussing how these rotations work is less of a discussion about Dual Pistols and more a discussion applicable to the entire Sentinel archetype. In short, there is absolutely nothing unique about adding Mind Probe -> Dominate to a Dual Pistols attack chain. Any Sentinel can do this and it can potentially increase your damage dealt if you slot these right.
Complementary Choices
Dual Pistols is a skirmish style set and fits in with an idea of being in close quarters. Any secondary which grants you a means of native stealth (e.g., Ninjutsu) will make positioning to drop Hail of Bullets easier. You can also place a Celerity: Stealth IO into Sprint and this gets stronger with stealthy sets.
Defense-based sets allow for the luxury to ignore set bonuses in your attacks and let you have free reign to load damage procs.
Other defensive sets can make use out of the debuffs present in the ammunition mechanic. Resistance sets may enjoy benefits of the -damage debuff on enemies. Regeneration-based sets (Regen/Willpower) can benefit from -damage, or the slow from Cryo ammo, or even buy some time with knockdowns.
Dual Pistols baseline damage is towards the lower end of the medium spectrum and moves to upper-medium with Incendiary Ammunition. This means power sets that grant additional damage like Bio or Radiation Armors bring some welcome benefits.
The Epic/Patron pools all have a lot to offer many builds generally speaking. These pools don't necessarily bring anything specific to Dual Pistols though. Ninja Tools does have additional defense debuffing, but again this is not specific to Dual Pistols. Furthermore, using any of these powers may conflict with concepts or create annoyance of watching your pistols appear out of nowhere (the no redraw option).
Dual Pistols has several fast attacks and the Sentinel version isn't nearly as reliant on Piercing Rounds as other ATs. This makes Hasten potentially optional since you can easily have enough attacks available. Hasten does allow for builders to push some extreme circumstances like abusing damage procs in a small number of rapid fire attacks.
Word of caution. Ok, not really a complementary choice, but more a warning on a potential trap option. Dual Pistols doesn't have Aim or Build-Up and many Sentinels may wish to squeeze these into their builds. This doesn't work out as well as it sounds on paper if you're going at this solo. This is especially true of using the Gaussian's Synchronized Fire Control + Tactics combo. If you use that Build-Up proc in Tactics, note that the chance to have it activate is incredibly small... by yourself. If you're on a full team, then each target of the buff (including pets that can receive Tactics) rolls a chance to proc that Build-Up effect on you. So you could use this to squeeze in Build-Up randomly while teaming, but for solo it will rarely activate. It is also completely uncontrolled no matter how you go about it. Decimation also has a chance for Build-Up proc. This one can work but again the caveat is that it is uncontrolled. If you are already thinking of using the 5pc Decimation bonus for the global recharge modifier, then you may as well use the proc to get there. The chance for it going off is fairly small (between 6-12% depending on power). However, Sentinel Dual Pistol attack chains can be pruned to just the fast activating attacks. This means the faster you hammer out your attacks the more chances you have to make that smaller probability into a reality. So it will go off in your attack chain at some point. Oh, and remember when I said that Epic/Patron pools Holds have long recharge times? Know what sets they can take (hint: rhymes with Ranged Attack Sets)? A Hold like Dominate can be a more reliable proc carrier for things like the Decimation: Chance for Build-Up if you are so inclined. Experiment! Explore! My way of doing things is not the only way of doing things!
Incarnate Abilities
I'm hesitant to offer hard line prescriptions here. Incarnates are best used to either shore up weaknesses or expand on strengths. You're also not locked into how many Incarnate powers you pick up. You're only limited to what you can slot at any given time. I have multiple powers in the Destiny category that I can swap out as I see fit. That said, it is tough to make blanket recommendations for a primary only and not a character. I'll try though!
For Alpha slots, this is going to vary based on what defensive power set you use. The Cardiac options can help resistances but also offer some endurance management. End management can be a welcome choice since hammering fast attacks will drain endurance. The Vigor options may be a nice perk for regenerating sets. Agility and Spiritual both have good uses but also bring additional recharge reduction which does impact your chances to trigger procs. If you're not heavily invested in procs, then either of those may be for you. The Musculature options bring more damage, and Intuition Radial does too. I lean heavily towards Musculature but these options are matter of preference.
There are several good judgments like Void, Pyronic or Ion. Pick one based on their secondary effects and/or if you like their targeting method (PBAoE, Cone, etc.).
Interface is fairly generic across all damage dealers and Sentinels are no different. The Degenerative chance for reduced hit points is a very good option for tough targets like Archvillains and Giant Monsters. Reactive can be good for clearing out hordes of weaker enemies. Diamagnetic can be good to add some defense due to the to hit debuff it brings.
Lore pets were all standardized and as such there is no specific category I recommend for Dual Pistols.
Destiny is going to vary wildly based on a complete character. You can't go wrong with Barrier as a generic choice, but the others will have uses depending on your secondary choice. Ageless works like another form of Hasten but the value of the effect degrades over time. Ageless can be a good option for builds needing more recharge which is especially beneficial to ones heavily invested into procs.
Hybrid options generally lead towards the Assault toggles. You have two options of Radial or Core. Radial adds a chance to do damage and Core adds a chance for a stacking damage buff. The chance to do damage works off PPM rules (the value is PPM = 6) and the chance for the stacking buff is 65% (thanks @Hopeling). Dual Pistols can make good use out of either option but Hybrid Assault Core does edge out ahead a bit due to the Page 5 scalar change. Still, Doublehit isn't a bad option to pursue if you prefer to have the bonus energy proc vs the stacking damage effect.