On the shaman thing: Not sure on the gear competition because they'd have different loot, wouldn't they? Sure its both mail, but your resto shaman would be seeking out healing gear, even downgrading to leather or cloth if necessary, while the stat differences would mean an enhancement shaman would get the opposite.

Also, wouldn't the totems compliment each other? Grace of Air + Windfury, Strength of Earth + Stoneskin, etc