I think the chance of failure is fine, but the health hit is just too high. It should be reduced slightly or there should be more than one kind of failure (chance to be blinded and have -50% hit for 6sec, or get shot up in the air, or perhaps just have nothing happen at all). With how there's only 2 possibilities... it works, or it fails and has a fairly high chance of killing me in a raid environment... I'll pretty much just never use it again. I acknowledge that they used to be too good back in WotLK days, but I do believe there's a middle ground somewhere... and that's not where they are now. All IMO, of course.