I have to agree about the effects on Simian Thrash - they it is obnoxious how overwhelming the giant balls of light are and that you can't even see your character's animation while doing the weaponskill.

I also agree about the potency of the weaponskill vs. its functionality. If you are going to make it that difficult to pull off, use buffs with, and have it incapable to use in a BR - then balance that difficulty with a stronger hitting WS or something to make it worth the inconvenience.