Wanted to bring an update to this situation. We've decided to go with the 1 tank/3 heal strategy, going Frost > Fire > Poison. We've had a few sub-20% wipes, one as low as 12%. I feel like this is the working strategy for us. We just need to get to the poison door with everyone alive.
My main issue right now is that I feel like we don't have a way of consistently getting through the fire door with everyone alive. We handle the boss in front of the fire door. We have 3 marks set up; one in melee, one at ranged, and one in between. The melee are at the melee mark, and the ranged are at the farthest away mark. As fire spawns on the two groups, both groups move toward the middle mark, until we eventually meet and stack there to phase the boss. While this usually works, sometimes we have people struggling to find a stacking point, sometimes the yeti charges into the area, etc. I feel like there should be a better way to handle this fire door.
Also, healing comp remains the same at Disc Priest/Holy Pally/Mistweaver Monk. We've replaced the Ele Shammy with a second Destro Warlock due to the Shammy pulling poor DPS. We're able to push to 24-25 stacks in phase 1, but during the blue door we struggle to get to 15 stacks when I feel like 20 is possible. Is it possible to hit 20 in this phase as well with our healing comp, with just better cooldown management?
Here's the logs from our recent round of attempts;
http://www.worldoflogs.com/reports/f3rqe51sr1osf2xy/