I have seen all the posts but never thought much of it until it happened to me. I'm not even full WH yet but I was on my Shadow and got smashed for 6000+ by a Sentinel. My jaw dropped. Never got hit that hard before, only seen it in these posts.
There had to have been at least 3-4 Sentinels on that team (pre-made) and every time I spawned I was getting smashed. 1 smash, 2 smash 3 smash dead. I only made it out of that game with 220k+ damage and my hardest hit was only for 3500+.
Use your Resilience, Force Wave, Blackout in certain circumstances, Force Speed to get out of other circumstances, Force Potency+Battle Readiness+Project to hit back hard, etc. I'm not saying the focus spec isn't ridiculous, but Shadows/Assassins have it really good in WZs. You can still compete well.
All that said, I can't stand those smashing groups. It has to be the dumbest spec I've seen in this game. I can't imagine how it can even be fun, except people like to win, even if through really stupid game-play.