I would've said The Line,but I've already voted it,Mark of the Ninja is also there,but I don't think it can fall into the GotY category for me,as much as I love it as a stealth game(lets me complete levels WITHOUT a weapon,the last few levels you don't have equipment at all,and the most ridiculous enemies are introduced).
Offtopic: Let's see how many "non-hipster",better known games are on the list compared to the total amount: Mass Effect 3,Far Cry 3,Halo 4,Brolands 2,CoD:BlOps 2,Diablo 3,AssCreed 3,WoW:MoP(up).A total of 8 out of 20,they're so easily excluded with the numbers,aren't they.
Persona and Tokyo Jungle are pretty big in the East I assume,but not in the NA/EU market,so not counting them.Guild Wars 2 hasn't really grown outside its own community,so...yeah,same for The Secret World,hence I don't include those either.The Walking Dead became popular as the episodes were released one after another and Dish-on-o-red felt like a "middle-class" game,an experiment,not a secure all-in investment with sure success and profit.