I finally cleared this on heroic after coming back with like 28k like on my tank. The final boss can really lay on the hurt! Anyway, my strategy is to wedge my guys into the spear rack on the right side in hopes they don't get thrown out of it. I tank the boss near to them, blowing heroism on the first transformation. It's important to get the rhino near the group ASAP! Like, almost on top of! You must have your back to your group so he throws you INTO them and not away from. If you manage to keep the healing going through this it's going to go down, but that's a big if...