Mana burn teams no longer work...Mana burn can only be used on any given mob once every (some period of time, I think its every 60sec).
Also I dont think the effect would even land before they got banished. I think it calculates agro before the spell effect is applied to prevent exploits like that.
You'd be better off highering a few wizards and sks to take out talendor when he's up. He is fair game. Wizards with the dragon bane nukes and ultra-HT SKs will take out a 32k talendor quite quickly.