Build Assist Needed for Dual Pistols/Invulnerability Sentinel

[BlazinBrazen]

I was up here looking at the Pine's Hero Builder and wondering to myself "self...((w'sup?)) what powers can I skip? ((I dunno))"...
So I now look to you in this wonderful community and wonder aloud "What can I skip, what should I take?" 🤔

[oldskool]

Well, Mr. Biggums, the answer to Dual Pistols isn't a simple one in my opinion.  Sentinel Dual Pistols benefited a lot from the proliferation to the Archetype.  That means you have a lot of options to choose from and your real limiting factor is going to be how many slots do you want to devote to things. 

I have a write-up on Dual Pistols in the sticky at the top of this subforum, but I'll try for a more condensed assessment here:

Pistols is a very good power for what it is.  I generally would not skip it regardless of what AT we're talking about. 
Dual Wield is potentially skippable but this only matters in builds with extremely high recharge. 
Empty Clips is a cone, and it only hits 6 targets at most.  Some people hate cones and avoid them like the plague. 
Suppressive Fire benefited from the Blast set alterations within the Sentinel Archetype.  The damage Suppressive Fire does is only surppassed by Executioner's Shot when using Standard Ammo.  With Incendiary Ammo, several other powers can over take this.  However, that is ONLY when considering baseline Single-Origin builds or builds using regular damaging Invention Origins (including sets).  Damage proc IOs (like Chance for Smashing Damage, etc.) completely change the value of Suppressive Fire and can make it one of the hardest hitting attacks in the set regardless of ammo type.  Cocaine is a hell of a drug, and so are damage procs!.
Swap Ammo --- take this, or question what you bothered with Dual Pistols in the first place.
Bullet Rain, well it is one of your best AoE's.  There is no point skipping this.
Executioner's Shot is the best single-target attack in the entire set. Skipping this is not recommended, but to each their own.
Piercing Rounds is a narrow cone with some unique qualities.  You can use this in your single-target attack chain if you want, but you really should build around doing so.  That said, this power is optional on Sentinels in the most generic of senses.  If you want to get into some real granular discussion on situational uses and IO building with it, I'm more than happy to do so.
Hail of Bullets, I can see reasons to skip this Tier 9, but I really don't recommend it.  Dual Pistols has no Aim/Build-up so there is no "click burst button -> fire off T9 nuke on spawn" gameplay.  It is due to the lack of that game play aspect that some may wish to skip Hail of Bullets. 

Dual Pistols, again my opinion, is one of the rare sets that has so many reasons to want to use each of the attacks that it can be very tough decision on which ones to drop due to limited slots.  That is not to say I think any of the attacks suck.  They just have certain circumstances where they perform well vs other sets with more clear outliers.  You can make a perfectly serviceable attack chain of just Pistols, Dual Wield, Suppressive Fire, and Executioner's Shot by level 18.  Then add on Bullet Rain for AoE, and you're good to go.  Everything after that is going to be situationally good or chosen due to some purposeful building.  At high levels of recharge, you can completely drop either Dual Wield or Suppressive Fire depending on what kind of IO build you want.  This is a rare case where you can make just about anything work very well here.

For Invulnerability:
You can skip Unstoppable. 
You can consider skipping Resist Physical Damage and/or Resist Elemental Damage.  Both of those passives offer small increases to your resistances but the decision to skip them is highly build dependent.  Most players do not skip them but they can be optional.  It just depends on what you're trying to do.

[BlazinBrazen]

Thank you for the input. I didn't know what I was getting into with Dual Pistols, but I like the animations (Gun-Fu) and thought it looked pretty cool. I am assuming Invulnerability is more or less like what it used to be (but with reduced values for Sents). I plan on getting the most damage I can out of this thru sets. I guess I'll play around in the Hero Designer and see what I get. Once I get a build i like i will post it for advice and critiques.