I guess I'm being contrarian this year by picking the latest incarnation of 40K to be my Game of the Year. Especially as the only people who seem to take GOTY seriously are video games people.
2017 has been a big year for 40K. The game has changed a lot. 6th edition was probably the upper limit for complexity that I was willing to bother with. By many accounts 7th was more faff that it's worth. 8th has really simplified things to a point where I think I actually understand the game I'm playing. Even if charging and the fight phase remain a big foggy.
Games Workshop have been getting more millennial (using social media) and engaging the community. From what I've seen on Facebook and through the Community Site this has been really well received. Not having to rely on crappy leaks from terrible websites to get info is a blessing.
We've got Primaris Marines. Wow. They're amazing! I love their poses and clean lines. They're incredibly fun to paint and are helping me push myself in terms of painting.
But why make it my GOTY? It's not the "best game" in the sense of game design. There certainly are aspects of it that lead to a negative gameplay experience. It's the holistic experience of it. Finding a good group of people to talk about rules, painting, modeling, and lore makes for a truly engrossing experience (dare I say hobby). It's the thing this year that I find myself thinking about in my default state. If I've got downtime I find myself thinking about 40K.
So yeah, GOTY.
 - maybe a second army of Blood Angles will change this.
 - comunitising the community