Well, the thing is that even with UVLS procced and Dark Soul + Haunt up, I don't do much over 100k DPS (on a dummy), which I find odd. I guess I'll try it out some more.
EDIT: About UVLS vs Wushoolay's for Destro.. Surely it's not even a competition, given the damage bonus Wushoolay's gives during the time it's ramping up, not to mention the fact that Wushoolay's procs twice as much?