Maybe this will end up being for the best, but no matter how much people might dislike Nomura, 12 was basically ruined by it in my opinion. Hajime Tabata is an interesting choice for his replacement, I'm willing to entertain the idea after he directed Crisis Core, but I have to wonder how well his vision and Nomura's vision will blend. I feel like a lot is riding on this game, especially given that recent quote about how they're using it to judge the viability of console rpgs. It's really baffling to see changes like that given what this game represents, though just about everything Square does these days is kind of baffling to me.
Despite making me worry about 15, I suppose this is at least good news for Kingdom Hearts 3. Personally I'm more interested in the former though, and I wish its fate was a little more secure.
That is generally true, but FFXV is hardly in the middle of development. There is already a demo planned and will apparently release next year - so within the next 4 - 16 months. Considering by the time it will be released it'll be 10 years in development, switching directors on year 9 is definitely not the same as year 4, 5 or 6. Who knows, maybe Nomura's stuff is already done on this game and he can now focus on KH3.