three things that stuck in my head from last night:
1) the pull - at least the group not in the vent channel with the tank had pretty bad information on when the pull would actually happen. Just looking at the enrage would not help, because sometimes he would pull pretty much at the same time, sometimes up to 10 seconds later or more.. most of the times inbetween. There are add ons that count down the pull for you (like one of us had, forgot who). Maybe the tank should use that if this keeps being a problem. (mainly it screws up pre potting)
2) boss being too close to the group. I realize that this is (until MoP) a hunter specific problem, but at least on Morchok our hunters are/were top dps, so pulling the boss too close during Crystal phase causes DPS problems for them due to min range.
3) some people, up until the very last try #15 (!!!) kept running to crystals as soon as they spawned. STAY close to the boss until AFTER the stomp, THEN go to the crystal.