The best team to go with is from my experience:
1.Prot warrior: Awesome AOE dmg, victory rush is just win in this spot aswell, and there banner pulls down all Bats, this is most likely the best tank for the job.
2.Warlock: Insane for bringing down the bats with improved Drain Life and if they are desto they can put rain of fire down aswell while pulling..
3.A nice AOE class, I used Boomkin because they have average AOE and they can off-heal which is great but its not essential.. I would most likely go for a Frost DK for the best AOE dmg. but any aoe class would do.
Also Its best to go 3 man because there is no point in 4 people, you kill the bats fast enough with 3 people. So alot more exp.