Now, I won't say I hated Mass Effect 3. I didn't. While nowhere near perfect, for the most part, it was fun. I enjoyed myself.
Yes, I occasionally missed the Hammerhead pretty desperately.
Yes, I wish there were some different minigames spread out among the gameplay to add some variety.
Yes, I wish that Shepard was able to touch base a little more with former squadmates, even take them along temporarily for the missions you meet them in.
Yes, I also wish there was more variety in the new squadmates.
And finally, yes, I loathed the original endings with a passion. I had heard that they were bad while I was playing through it, but I thought, "Well, the end can't be that bad, can it? I mean, this is Bioware we're talking about, one of my favorite developers, right next to Bungie and Valve. They wouldn't shoot their baby in the foot right at the end, right?".
Then I got to the end and... Shit. I didn't really feel anything at first. Shepard lived because I played the mediocre but mildly fun multiplayer, my squad was stranded on some strange planet, and it looked like the galaxy was not only screwed, but I made it so one of my former squadmates essentially sacrificed himself in vain. As well as killing EDI.
First, I disliked it. Then I grew to hate it, but played through anyway because shit, I had a Femshep waiting for me to play as her, and I wanted to focus on the good Mass Effect 3 had to offer. But the fact that so many questions as to how the galaxy would end up after all of that were unanswered pissed me off the most. I was fighting for the galaxy, to save it and destroy the Reapers. So did my Shepard succeed or what? There was no closure. And that is what an ending is for.
Ultimately though, the worst part about the endings, in my case, was the fact that it was so out-of-nowhere, so starkly different and poorly written, that I could just ignore it. I was so indifferent and disgusted with it, that I ignored it with ease, and focused on the good, and really, that insulted me. Bioware at least had the talent, so I thought, to make an ending that would be hard to ignore, good or bad.
Now sure, I have other gripes. The multiplayer could have been better, they should've put more effort into the romance scenes for say, Garrus or Tali. Or even Tali's face.
As for the Extended Cut, it at least addressed some of my main issues. I know the galaxy isn't screwed now, my squad should make it back to civilization safe. The Reapers are well and truly dead. The endings still suck, but at least there's proper closure now.
Anyway, I'd still nominate Mass Effect 3 as Game of the Year, because it was one of the games that defined this year for me, in gaming terms at least. I wouldn't say its the best game this year. I won't say it's the worst either. It was above-average, all things considered.