I've been playing WHM more often since SCH Nexus is done, and the margin for error is definitely slimmer on WHM. Not only can the healer afford fewer mistakes, the tank can't afford to slop, either. Once Bene is shot and Swiftcast is used, that's it for panic heals. Combine that with the necessity of actually paying attention to your enmity table once in a while, and it's a very different experience than playing SCH.
Bad tanks are the bane of my WHM game. Bad DPS can be healed if they don't die outright, but bad tanks do things like stop-and-start pulls that cause aggro to go nuts and spread mobs everywhere, making WHM life a lot more difficult.
