Shaman race choice without torpor.

[Orruar]

Where do you get this 20% number from? A slowed mob will land a bash couple minutes at most. That means you have roughly a 5% chance of being interrupted on torpor, assuming you don't watch the incoming melee rounds. And if you don't watch the incoming melee rounds to time your long spells (torpor/dots), you're going to be interrupted far more often by straight up melee damage interrupts than by bashes.