At 90% Morchok will clone himself, splitting into two. The raid will need to split into two groups (1 tank, 3 healers, split dps). They'll be tanked on opposite sides of the road, meaning we'll have to clear a bit more trash before pulling the boss.

Kochrom, his clone, is by far the weaker of the two. When doing this in 10 man heroic, we noticed Kochrom didn't do as many stomps or spawn as many crystals. So it's ideal to have your stronger healers assigned to Morchok's group. Morchok has a habit of stomping and throwing out crystals right after.

Healers need to keep the double stomp eater topped off, same goes to the raid, before we move in to the crystals. Good time to pop swiftmend on the target for the burst. Not getting topped off in time before the crystals is one of the main reasons people will die (other than someone getting too close to the boss and taking the double stomp when they shouldn't).

He'll enrage at 20%, so be sure to save lust for then.