I'd have to go for the 4 druid team. Not only for the healing (if you are moonkin you have to change out of form to heal, but not to much of a deal). The second thing that makes them wonderful is the ability to res.

It is such a pain in the backside having to try and gather a team together when one or two have died.
Especially when they are at other ends of the BG and you invariably get jumped or die on the way back.

Opener from stealth, quick shift forms out of some forms of CC, heals, Battleres (occassionally might be nice),Treeants all would make things kinda interesting.

Locks would be sweet too- especially if you could persuade a healer to run with you.
I love that teleport ability. Stand up a hill at a choke point. Dot everything passing by then teleport somewhere else when they head for you. fear them off, drain life for some healing, death coil too.