As much as I like Kingdom Hearts, KH3 and the other KH games aren't really GOTY material. They're fun games with a lot of heart but they're inconsistent when it comes to quality. They hit some high highs, but at the same time they hit some terrible low lows and that's now what I expect from a GOTY. If we talk about parts of the game(s), then some of them are definitely GOTY material, like Quid said.
Yeah, if we're talking GOTY, it'd have to be on the same level of God of War, Spider-Man PS4, The Last of Us and I don't think KH3 plot-wise can measure up to that. Not when there's so much criticism surrounding it. It'd be great if it did and it really depends on what comes out this year, but Kingdom Hearts is a series that's not the most accessible or has the best writing, and those are knocks against it.
Now with that being said, I LOVE KH3. And a GOTY isn't gonna make me love it any less. So whether it wins or not, is really more for me wanting the whole team getting their proper due credit they've earned. It's already a winner in my eyes, so I want the devs to feel like they won too.