Killing the priest is actually as easy as having one nuker with two AEO spells.
As soon as the clock reaches 1:40 (or 3:40, 5:40 etc), the nuker moves to the wall of the hut / building that the priest is in.
Tab until you've targeted him, then cast Fire storm and Meteor Strike. One dead priest (provided your fire is at 11 or so).
Also, the one group I was in that succeeded in this mission (2 primary plus my ElMo) wasn't all that well organized, but the mission doesn't actually seem overly difficult. The damage you're getting from the mobs isn't all that great (although 3 monks may have helped with that

), it's just that the ress clock seems to panick people.
The Monk boss was very easy, we didn't even do him last, we killed the right group first ,then before the clock was reset, my group attack the monk boss group. I just rushed in, nuked the priest, and we mopped up from there.
Seriously, one nuker on clock watch / priest killing duty is all you need.
Creston