There's plenty of cries of "nerf please!" when people see what happens here, but how often are you going to run across a situation like this? Fifty Alliance tightly packed in a little elevator unable to see what's above them? I think there are three locations like this in all of WoW. Assaulting Thunder Bluff may suck when the Horde knows you're there, but it's not that big of a deal overall. Hilarious when it happens, but it won't happen often. In smaller scale situations like a one on one or a one on two... well, don't get between the Shaman/Mage and the cliff, and you'll be fine, eh?