I've cleared it with the following group:
- warrior tank
- shaman dps
- druid dps
- hunter dps
- paladin healer

For me this fight is relatively easy, because my group stacks a lot of stamina/health buffs + the hunter provides nature resistance. Healing through the aoe is a simple matter of casting flash heals on the dps and the beacon of light auto-heals the tank. When the boss switches to elemental mode for the first time, I pop bloodlust and burn him down as quickly as possible to reduce the aoe damage. I also have a key that makes the dps take a step back (and makes the tank charge). I use this key to simply step out of the puddles every few seconds. And if all else fails, I pop tranquility on the druid and the group should be back to full health