I spent a lot less time playing new releases this year, so there's no straightforward winner for me, unlike last year with the Witcher 3. Plus, I never got around to Blood & Wine so I can't even get it in that way.
1st: The Division. This is shocking to me, because I loved the game, then hated it, but then, after all the patches and, most importantly, Survival Mode, it came roaring back.
2nd: Overwatch. I'm crap, but I still had a blast playing this. Joyful in its way, polished to the finest sheen. A minute to learn, a lifetime to master. Like all games of this nature, the stronger the focus on meta gets, the less interested I become.
3rd: Stardew Valley. All hail the one man show. Not my genre, normally, but it was charming and delightful.
4th: X-Com 2. I didn't like the mobile base thing as much as I imagined, but it's still tactical combat goodness. Not the perfect iteration of the genre for me, but on approach.
5th: Reigns. The first mobile game to make my end of year list.
Game that would be number one with a bullet if it were out of early access: Rimworld
Games I haven't played yet: Oxenfree, Dishonored 2, Hitman, Civ VI, Watch Dogs 2, Steep, Mafia 3
Games that disappointed me most: Deus Ex, No Man's Sky, Stellaris