I assume you use Choking Gas and Incendiary Arrows back to back, initialising one after the other ends, and using the other interrupting shots while both preps are recharging and the prep on u has ended.
I tried this out before, but imo it's not as effective as the 'traditional' Practiced Stance/Choking Gas/Tiger's Fury combo, which has a lower preperation time (since u only need to prepare 1 prep instead of your build's 2) but is only effective against casters.
Troll Unguent, Tiger's Fury, Distracting Shot and Res Sig are ok, but I feel you should ditch Serpent's Quickness, since it, being a stance, does not stack with Tiger's Fury (and u'll want to have Tiger's activated as often as possible to be an effective interrupter).
All in all I really don't think the build u mentioned is too flawed. A little skill adjustments here and there should increase the build's interrupting efficiency.