When I think about game of the year I don't think about sequels or popularity of a game, to me a game rated 7.0 could be game of the year even though it didn't score well.
This year I would have to give it to Skyrim. Not because of the hype or how good the game is, but because it is the only game you listed that actually shows ambition, iteration and evolving gameplay. It is the only title that isn't playing it safe and trying new things.
The other titles listed are great games but they play it safe and are unwilling to rewrite the book on their franchises. Skyrim has added and tweaks so much of its mechanics it doesn't play that much like previous games, it makes more sense and is way easier to approach by gamers who aren't into RPG's without dumbing it down for existing fans of the series.