My guild downed him yesterday for the first time and we had whelps, storm drake, and slate.
We released whelps and storm at the same time. I tanked halfus and our OT, who is a paladin, tanked the whelps and the drake. DPS burned down the storm drake and when I got to 9 stacks of the healing debuff the OT HoP'd me to clear the stacks and I kept tanking halfus. By the time I got another 7-9 stacks the storm drake was dead and the pally taunted halfus and we finished off the whelps. Then we proceeded with a tank swap the entire way through with a mage blinking on the 3rd furious roar.
One thing I noticed was that I was getting hit extremely hard and had to rotate out all my cooldowns. I was dropping from 100 to 0 so fast at times it looked like we wouldn't recover but I was able to get topped off quickly at times.
So maybe avoidance is the way to go instead of stam or something, I'm not really sure. My guild is currently 5/12 and I feel like this boss hits like a truck compared to the others I've encountered
Here's my armory:
http://us.battle.net/wow/en/characte...ADrik/advanced