I think it's more akin to the fact that aside from the last ten minutes, Mass Effect 3 is a very excellent game that's almost flawless.The sci-fi action role-playing game caused a bit of a stir this year, but the controversial ending didn't stop it from being chosen as the best game of 2012. Perhaps it was the Extended Cut that quelled the uproar and put Mass Effect 3 on top for Game of the Year. Maybe the continued DLC support, with the most recent Omega having just come out in November, kept it fresh in the minds of gamers everywhere. Whatever the reason, we here at The Escapist are officially calling Mass Effect 3 our community-picked Game of the Year 2012.
I wouldn't say that it's the DLC support, since people here don't seem to care much for the multiplayer, and the paid single player DLC has been overpriced each time ($35 USD for 4 or so hours of content? The hell?), not to mention that From Ashes was clearly cut from the game to sell as day one DLC, and that Omega wasn't that good.