* Note that I still haven't actually played The Witcher 2, and fully expect it to eventually shake up my 2011 ratings
What I will say is that it all boiled down into "the return on investment wasn't there".
I can better my skills, and all I will get is the occasional perk point... except the perks excite me so much I have 11 I never used, and never really will feel the need to (on the longshot assumption that I'll even play the game in the next 3 years)
I can invest hours completing quests... and the loot I get is likely no better or worse than stuff I can get at the corner store. I don't even feel like the quest giver cares five minutes after I complete the quest.
I can invest 90 hours into a character, and he's still the same cardboard cutout that stepped off the cart in Helgen. There's never any real chance to develop a real personality to him or her.
Whereas...
...in Deus Ex, I might have all of the abilities I really need and want, but if I gain a level, I can choose what abilities I "need" most in a heartbeat.
...in Deus Ex, I know why *my* Adam Jensen is doing what he's doing, because of conversations he's had and things he's said.
...in Mass Effect, I know *my* Shepherd is a nice guy who is still capable of making hard choices, because that's who he has made himself.
...in Dragon Age, my first meeting with Morrigan had certain responses that I "had" to choose, because I literally, by that point, couldn't imagine my character acting any differently.
...and so forth.
Skyrim just didn't reward me. It distracted me, and that came to an end. I haven't felt the need to go back.
As for why Arkham City wins, I have a very hard and fast rule about what makes a game instantly on another level than most games: if I am reacting emotionally to content, then it's a cut above. Of the 2011 games I played, that means DX:HR or Arkham City, and I went with the better gameplay as my decider.