I really hope that this means we'll finally be getting a story trailer this winter! Eep!
Anyway, I really truly think that Kingdom Hearts III is much farther along than Square Enix wants us to think.
Granted, I doubt that they're in post-production. And I even doubt that they have the master copy of the game complete yet, but I'd like to imagine that they're at least getting somewhere close to that.
They've been working on this game for three years (if not a bit longer than that, because I imagine that they were working on III for a small bit before they announced it... Though switching from Luminus to Unreal Engine 4 probably did cost them some of their work), and that's how long it took them to make both Kingdom Hearts I and Kingdom Hearts II, IIRC. And it looks like they're going to be working on the game for one more year, at least. And I do think four years is a considerable amount of time to get things done in.
I know that KHIII's a much more ambitious title than any of the others in this franchise, though, and that this is really the Osaka team's first time making a game for consoles (as Re:Chain of Memories was just a remake of an already existing game), so that should be taken into consideration. I'm not going to deny that.
But I still think they have a lot more done than they're showing, which is why they keep showing older builds of the game (i.e. the Jump Festa KHIII trailer, I mean)--because they want to surprise everyone when they have a huge news blowout that shows how much of the game they really have completed.
But there is just too much going on for me not to believe this: Final Fantasy XV wrapping up production (where afterwards, the Tokyo team will help even more to get KHIII out the door)... Nomura saying that he has a lot of anniversary surprises lined up for us next year (which a lot of us took to mean that one of them is KHIII releasing at the end of next year)... the two Sora figures... different people saying they've done voice work for KHIII now... Square Enix hiring for post-production when it comes to KHIII (though I imagine they probably hire people for that early)... the fact that they've had a whole year where they've done nothing but work on this game, and haven't even had any press about it... and now this.
So until proven otherwise, I'm going to believe that this game's development is going steadily and that we may get it sooner that what we're thinking right now.
Maybe not by much (and tbh, the II.8 delay might have set it back some), but I do still believe that this game is at least somewhat more complete than we've been led to believe. Just how much that is, however, is yet to be seen.