There is a certain risk involve when you start hyping the game too early. Fans will start getting excited way too early and will start building expectation for the game. The longer it takes for the game to arrive, the higher their expectation will become to the point where their expectation becomes so unrealistic that they will be disappointed with what the developers have to offer.
We are not saying that the fans will be disappointed with Kingdom Heart 3 when it arrives but we think that Square Enix might have started the hype train a bit too early but that might be because they never expected the development to turn out this way.
The Kingdom Heart 3 game was expected to arrive last year after the trailer for the game was released at E3 but Square Enix later came out to announce that they will be delaying the game as they will be switching the game to a new engine.
The last we saw was the new trailer that was released with the Kingdom Hearts HD 2.8 Final Prologue. Based on what we know now, we would be lucky if the game ends up arriving this year.