Still haven't played either Witcher of MGS5. I imagine it'd be one of those. I'll just have to go with Splatoon instead though. And I'm 90% sure that'll be usurped by Xenoblade X.

Out of the games I've played so far this year:
1. Bloodborne (This is my favourite game of this year. I'm a big fan of the souls series and really enjoyed bloodborne. I found it's graphics great and the whole gothic mood superb; the mechanics were faster paced than any souls game which made you play a lot more offensive which was a plus. I don't think this game will be the goty though because of it's small fanbase - lets face it, souls games never have a big fan base anyway, mainly I think due to their difficulty)
2. The Witcher 3 (This will probably be the goty. Great story, solid graphics, big open world, nice mechanics... Having a bigger user base PC-PS4-XB1 than bloodborne helps as well. It was also a very anticipated title for years in advance and reviewed really well)
3. Rocket League (Really addictive and fun game but can't compete with the other games on budget, graphics, anticipation, wow factor etc)
4. Splatoon (I don't own the game but I've played it a lot at my friend's. It's really fun, I give it that but I don't think it will be the goty mainly because of the reasons I said for bloodborne and rocket league. It has a small fan base relative to TW3 and RL and you can't compare the wow factor to games like bloodborne and TW3 based on graphics, budget etc)

Games I haven't played:
MGSV (a definite contender for goty)
Batman (I don't think it will be a contender due to the PC release fiasco and to it's lack of originality - It's the 4th instalment of the series)

1. Metal Gear Solid V: The Phantom Pain
2. Batman: Arkham Knight

It's Bloodborne.. It has nothing to do with "The Bourne Identity". Everybody keep making that mistake. lol

Oh, it's obviously also GOTY 2015. No doubts about that!!

Mario maker.

I haven't played Bloodborne, Batman or MGS5 yet, though I have them all ready to play. It says enough that Mario maker got bumped in before the others, it's simply the most inviting title which hasn't let me go 1 minute since release.

This year so far I played:
The Order, Surprisingly fun gun play when it lets you play, boring story.
Grim Fandango remastered, still a masterpiece
Toren, didn't grab me
Project cars, great racer with some serious flaws.
The Witcher 3, great characters, good but flawed open world gameplay.
Nom Nom Galaxy, very addictive and fun.
Everybody has gone to rapture, great immersive experience, best sound this year, could have used some puzzles.
The vanishing of Ethan Carter, looks great, but not as good otherwise.
Rocket league, great fun in 4 player splitscreen
Splatoon, my kids love it, not my cup of tea
Tearaway Unfolded, Looks great, fun gameplay when it lets you play. Haven't touched it since Mario maker.

Other than that I played a lot of Elite Dangerous, Drive Club and finally got around to play through GTA5 (awesome sandbox with restrictive missions as usual, skipped the barely watchable cut scenes)
I also played a few more times through Journey on ps4, still great.

Bloodborne so far (Got bored of Witcher 3 after a few hours, I'm tired of open-world games now) but my GOTY will be Halo 5!