I'm really happy with my current set up - feral tank, resto shammy, +3 elemental shammies. I have 7 accounts, though, so I could bring in an extra one or two for some raids - so as I'm contemplating leveling a worgen in Cataclysm I'd like to choose a class which brings as much synergy and utility as possible for slot 6 in raids. Looking at it now, I'm leaning towards Warlock - summoning is always nice and Curse of Elements will at least help with fire damage. But is there another class I'm missing? And advice? Bueller?