this guy use shaman. http://youtu.be/qFAzeq7jAGU
shaman and suc debuffs do stack. I did boss 3 tonight with pd, cupid, shaman, suc, druid, champ. Lasted full 3 mins, 55 mil damage. Achieved perma stun after 1min 53 secs. I think due to shaman having heavy blow 4/5... But before perma stun, boss stun interrupted pd and stopped the stacks. The boss hit like a pansy though, and couldn't get my heroes even to half health.
If you can't perma stun boss, I can't recommend suc + shaman setup enough for any of the bosses.
He also rocks in Mesa.. Allows us to do SM3: without him, the boss just hits too hard. Just need him to 100+ 3/9 to do the job.