Skyrim is the newest game and it is still currently in hyped mode.
So, It is absolute that Skyrim is winner in such polls.
However, It can not be a "Game Of The Year", moreover not the "GOTY OF EVERY YEAR".
It is just overhyping a "new" game, that's all.
To talk objective
Skyrim is nearly as good as Morrowind in exploring, sightseeing and watching sceneries.
It has also the best crafting system in TES series (in my opinion).
However, It has the worst user interface in TES series.
Dumbed down the game so much that you can not even see information about buffs, their durations or how many buff you have at that moment. OK, I admit clearing GUI a bit can be helpful to players. However, unnecessarily amount of wiping functions of the game, makes it really dull experience.
Sadly in inventory management, item variety, menu functions, and similar aspects, it is the worst in the series.
Also the game engine is outdated, you feel like playing the game in low settings, thanks to the insufficiency of graphics, textures, lightning and shadows.
Battlefield 3 is better than Modern Warfare 3 in gameplay, graphics and multiplayer. However it's singleplayer story is not as meaningful as MW3's scenario. MW3 is very weak compared to BF3. I can admit MW3 is better than MW2 and Black Ops, however I really bored while playing singleplayer, even if the story was interesting.
Therefore I don't think both BF3 and MW3 is suitable for GOTY award.
Minecraft can be GOTY, has very interesting sandbox elements, enjoyable multiplayer moments.
Witcher 2 can also be GOTY, possibly the best RPG in this year.
Deus Ex 3, was a disappointment for me. It was something like "Deus Ex 1, for the consoles". It is better than DE2, and almost as good as DE1, however consolization of this game disturbed me a lot.
MY vote is on Portal 2. Every genre of players can like this. From the Modern Warfare-type players to the Battlefield type-players, from the Dragon Age 2-type of players to the Witcher 2-type of players, everyone played it and liked it.
Therefore I think it really deserves the GOTY award for this year.
Awesome story, interesting characters, varied gameplay, creative level desing makes this game awesome.
I finished this game 3 times consecutively and never bored in a moment.