Normally we have the tank pull him far enough from the sanity well that he doesn't stand in it but close enough that the tank can remove the debuff. Tanking him close to the mobs causes everyone to have to avoid his aoe as well as the mobs we are fighting.
I have a question for Master of Flame spec. If there is 2 MoF in the group does the swath of destruction debuff stack. I will be testing tonight but I was curious if anyone knows or has tested already.