So what's the deal-- do we elect our leaders or what? Obviously, I can't think of a single leader in WoW that's actually elected, by the players or anyone else. Thrall is a Warchief, so you'd assume he has to be overthrown, and that seems to be the case with most of the faction leaders-- King Bronzebeard isn't leaving anytime soon, and though the boy king of Stormwind sits pretty precariously on his throne, there's probably a few legal strings (and big black dragons) holding him in place. I can't think of any seats that might change hands anytime soon.
Save one: you have to think that if anyone's days are numbered, it's Sylvanas'. We already know she's got a bone to pick with Arthas, and if anyone isn't coming back from Northrend ali-- err... undead, it's probably her. Who would take over Undercity then-- Varimathas? If something did happen to Sylvanas in Northrend, the whole Horde might be upset, and considering Jaina may end up in on the action as well, no one's probably safe.
Still, even if our leaders get toppled anytime soon, I doubt elections are just around the corner. I don't think we really live in a democracy here-- more like a military dictatorship.