I've completed Marau with a 70 priest and 4x46 mages (Bah a 70, that's no fair)
I've been trying to let the mages deal with mobs and just keep them up to see when i'm getting trouble with to much incoming damage.
I burned one down before it could reach me, ran far back and waited for the next one to come in range and repeat.

First time in the room I was nuts enough to try to burn the whole room down with aoe,
but they took all aggro from my priest and died instant.

Biggest issue was finding my way in the instance,
I usually had guildies to help me find the way