If there ever was an encounter in which Atonement-specced priests really stood out, this would be it. Aside from that, Halfus on heroic mode is a great test for healing leaders and raid leaders on the art of syncing defensive cooldowns.
Objective: Can your healing team help the raid survive the first minute of the encounter?
Once you get past that first minute, the hardest part is over, and your raid will get there. In this post, I'll show you a textbook case of cooldown planning from start to finish.
On the the matter of cooldowns, it looks like shaman will be getting their own fairly soon.
For restoration druids, Malfurion's Gift appears to reduce Tranquility by 2.5/5 minutes. The actual effect of Tranquility has not changed. If I were to guess, I'd say it would get modified further for reduced incoming damage while the spell is being channeled. No confirmation yet either way.
Spirit Link Totem: Reduces damage taken by all party and raid members within 10 yards by 10%. This lasts 6 seconds, and every second it is active the health of all affected players is redistributed among them, such tha teach player end sup with the same percentage of their maximum health. This counts as an Air totem and has a 3 minute cooldown.
So how does one survive Halfus in the 25-player raid?