Personally i'm just going Haste>Crit, everything else after that is meh, although mastery looks interesting.
Also did some testing with shadow crash. Due to the behavior of cascade and how it worked if you got a buff mid bounce, it wouldn't count said buff until after it hit. I tested it with Voidform but for shadow crash. It appears that shadow crash does not care when you activate Voidform, just as long as you do so before the hit. Also at 110, the highest non crit hit i saw from shadow crash was about 177k in 792 gear, almost double a mind blast.