I just did this on normal with my 74 pally, 3 mages, and druid healer. What I did was tank and spank until insanity. Once he did insanity I spammed arcane explosion on the mages. After the mages killed everyone with AE I made focus one of my mages and nuked the rest down. I kept spamming wild growth on my druid. Eventually everything died. It took me two insanity phases to kill him. I guess having aoe on that fight really helps. I doubt it will work in heroic because the mobs have 12k health. My arcane explosion hits for about 700 damage at lvl 74.