Hjarki

I tend to agree with the 'make it faster' notion. Dropping Impale down to Lunge's activation time and reducing the overall damage scale by a proportionate amount would make the set flow a lot more smoothly. However, because activation time is tied to animation, it's often difficult to change the activation time of powers - you have to subtract animation frames (which may make the power look strange).

With the changes to Lightning Clap, I think it would be worthwhile to switch it with Thunder Strike. Thunder Strike is a far penultimate power than the revised Lightning Clap (which is, in turn, a far better fundamental power).

I think the Master Brawler expansion is a good idea. I think the change to the power is a terrible one. The change makes Master Brawler a 'dead power' for the purposes of set slotting. In a set that already has extremely limited slotting opportunities, this is a significant nerf. Losing the absorb also makes it directly inferior to Practiced Brawler.

Does anyone happen to know how procs work in Attune?

Purple triangles doesn't cover Sleep effects. I haven't tested it, but a Sonic Stalker should theoretically be able to keep an AV asleep permanently as long as the only attack hitting it is Assassin's Whisper.

Dark Armor with Obscure Sustenance doesn't have the classic problems with endurance, so pretty much any set should work well. Martial Arts is a strong set for farming. While it only has one AE, it's a very good AE that can slot Force Feedback. I haven't tried it, but my suspicion is that between capped S/L resists, Obscure Sustenance, Cloak of Fear and not completely terrible Defense, you should be able to survive just fine. I usually go Psi Mastery on my farmers due to the endurance reaction and the extreme range on Psi Tornado (this can be invaluable for not having to run all over the place when you want new mobs to kill).

Elec/Psi/Elec Sentinel works for me. Devour Psyche is a clunky recovery/regen power. But it's a great -regen/-recovery power against single tough targets. Since Elec Blast doesn't really need recovery bonuses anyway, it works out well. The set as a whole has a fairly comprehensive set of status/debuff protections even if the resist/defense aren't particularly great - fine for a build that can operate well outside of melee and can cripple enemies with end drain. In terms of the Aura, I think triple HO Acc/Control, Unbreakable Constraint proc, Call of the Sandman proc, Coercive Persuasion proc probably works well but I haven't really looked too deeply into how effective those procs are.

Seismic is a lot stronger than it may initially appear. All of the powers also reduce the remaining recharge of your Seismic Blast powers. This makes it one of the best sets for procs (since you need to slot so little recharge in the powers themselves) and a set that needs minimal recharge. It also ends up having one of the fastest recharging ultimates due to the set benefit.

The Defender inherent and procs are both additive damage, not multiplicative damage. So there's no interaction between them. Presuming I did the math right, everything I said should be true regardless of how many allies you have, how many reds you've chomped, etc. I will note that I almost certainly did the math based on having no recharge slotted into the powers.

Is this change applied to the similar Static Field as well?

Debuffs intended to protect players aren't really all that useful - even on Defenders. In general, the more you need them, the less effective they become. That -5% hit or -8% damage is fine against even con minions. Against a four star AV/GM? They might as well not even exist. Status effects, on the other hand, can be useful. Stone Melee is arguably a better Control set than actual Control sets, with an easily stackable AE Disorient and Mag 4 ST Hold. And, of course, the status effect all Tankers have: Taunt.

I play this combo, albeit in a very different fashion. From Staff Mastery, I take Staff Mastery and set it to Mind. Then I do: Precise Strike (Superior Might of Tanker 4p; Hecatomb proc; another proc) Guarded Spin (Fury of the Gladiator A/D, proc; Obliteration D, proc; Armageddon proc; LotG recharge) Serpent's Reach (Gladiator's Javelin A/D, proc; Apocalypse D, proc; Explosive Strike proc; Perfect Zinger proc) Innocuous Strikes (Armageddon 5p; another proc) I don't take any of the spenders or Mercurial Strike. In a ST fight, I can go PS->GS->PS->SR. For multi-target, I can just rotate the two Cones. Since I Hover, this generally allows me to blanket most spawns. For Bio, I skip Parasitic Aura. I use 2xEradication 3p and 2xMocking Beratement 6p to get enough F/C/E/N to reach incarnate soft-cap in Defensive (and obviously well above regular soft-cap in Offensive). I hard-cap S/L and don't worry much about other resists. 6p Preventative Medicine in Ablative for some more recharge - between my two purple sets, the ATO 4p, Preventative Medicine, the two Mocking Beratement, 5xLotG and Mind, I've got enough recharge for the build. For pools, I take Fighting, Leadership (Maneuvers/Assault), Leaping (Combat Jumping) and Flying (Hover/Fly). I use Psi Mastery (Dominate w/Unbreakable Constraint and Harmonic Mind). While this obviously isn't the maximum possible dps out of the build, it will generally deliver a lot more dps than straight-slotting the offensive powers for damage. Since the AF of melee cones is relatively low, those procs don't perform all that much worse than they would in ST powers (and certainly better than in a PBAoE aura).

For ST, I tend to go AB->HB->AB->WJ->WJ, with Water Jet as heavily proc'd as possible. Dehydrate instead of Hydro Blast is also an option.

You consider asking if you care about perma-PA. perma-PA is primarily of concern for builds that intend on solo'ing AV/GM. They need perma-PA because they don't want gaps in taunt coverage that might expose them to attacks from those AV/GM. However, for most builds, this isn't actually all that important because Phantom Army is simply a damage cooldown.

It also appears he's running a sub-optimal rotation where he's only using ET once (rather than twice). I suspect he also didn't split the ATO minimize the internal recharge on Assassinate (and thus get the maximum proc rate on Hide before TF). In terms of raw non-proc/non-pet ST damage, my experience is that EM Stalkers are in a class all their own.