Overview
At the start of the fight we have all dps start out on the left leg then shortly after the first stop everyone switches to the right to give the boss a pathway that generally leads to crushing all initial volcanoes without creating the need for a harsh initial turn. Our raid then splits into two groups, the Leg group which roams around directing the boss, and our Add group which positions just on the edge of the island where we entered. When the boss reaches about 40-45% we start positioning for Phase two Bringing the Boss close to the entry point where our add group is positioned. At 35% have our group stacked together (with the tank facing the boss away) for phase two and we pop hero and have the entire raid switch from adds to legs which quickly pushes him below 25% with momentum to drop him as everyone is already full swing into their rotation.
DPS Breakdown
Legs: (Ret,Arcane,Destro)
As leg we utilize cooldowns to make sharp turns and not just simply to destroy the boss. Knocking out volcanos is the main objective. Our group uses three very logical raiders for this task who constantly direct the boss as a team, we all make calls when we see something the others might not see. In addition, we have the Lock and Mage macro whisper the Ret paladin with one frequently used ability as he has the best perspective on the direction of the boss. Both feet have raid markers so that the Ret Paladin can make judgement calls in adjusting the dps distribution on the legs
Example Macro:
#showtooltip Arcane Blast
/w Ex %t
/cast Arcane Blast
Adds: (Survival,Survival,Arcane,Prot Pally).
We keep our Add dps spread until his Obsidian Armor is gone or nearly gone, at which point our arcane mage that was formerly on adds will switch between the boss and the big single add being sure to prioritize the latter. Our hunters rotate misdirects for each add or pack of adds to our prot pally.
Healing Breakdown
Phase 1:
We put our Disc Priest and Resto druid in the add group while our Resto Shaman runs around healing the leg group. Healing in this fight is very manageable until phase two as long as people are not getting hit by the lava from craters.
Phase 2:
Long before phase two starts we are already getting in position. Our disc priest is marked and everyone stacks on him, he drops a Barrier, our shaman drops a Spirit Link Totem and our Druid Pops Tranquility. And hope for the best
I hope this provides a little more insight on the specifics of the fight. And perhaps you can utilize this with some adjustments on your strategy.