We took him down after 5 wipes yesterday and he really wasn't that bad once you got the interrupts under control. We was 16/16N last tier and our average ilvl was somewhere between 485-500.
The way we did it was:
1st door: Our hunter took care of the stonegazers while the rest nuked down the first wastewalker, when the second set of wastewalkers spawned we marked the first and had our warrior/shaman interrupt that one while the rogue/monk handled the other. I used Mass dispell pretty much on cd this phase since the group is pretty stacked up on the adds.
2nd door: Everyone nuked the priests and the hunter took care of any Effusions, interrupts were handled the same as the previous door.
3rd door: We pop bloodlust and nuke the living shit out of the warlords while the tank kited away from the frozen orbs and dispelled when people reached ~4-5 stacks of the debuff.
4th door: Aoe'd them all down while staying out of totems.
Last phase: Burned down War-God Jalak as fast as possible and then simply nuked down Horridon while the tanks/healers rotated cooldowns to keep the tanks alive.
Our setup:
Blood Death Knight
Protection Paladin
Discipline Priest (me)
Holy Paladin
Destruction Warlock
Assassination Rogue
Elemental Shaman
Survival Hunter
Windwalker Monk
Fury Warrior