An alternate method I've found works is to bind everyone's strafe keys together. When he starts his AOE you strafe the whole group to the right/left out of range. Line up and dps again. Rinse and repeat. It's hard to get down considering after the first time he doesn't line up properly, but I can usually avoid one or two of the aoe's with this.

Healing through the AOE is viable as long as your priest has enough health/mana to do so.