I mean they've shown so little of it that I'm still on the wait and see fence about that. All I can say is when it does come out I get the feeling a lot of people are going to be there sitting are going to go "It took them that long for this?".
I mean FFXV may be a good game but it sure doesn't look like a game that took nearly 10~ years to come to fruition, I expect the same out of KH3 and I love the series.
That's because FF15 was only really started in 2012, so around 4 years of actual dev time. FFV13 was in preproduction for most of the time it was around as there was not staff working on large portions of the project due to various technical constraints, internal teams shuffling around taking most of the staff away from the Versus project.
It was for all intents and purposes on the backburner compared to FF13, FF 14 and later FF14 2.0 which had a large portion of internal staff on it to get it turned around in record time.
KH3 was not even a thing until DDD was finished in 2012, and they already had to reset themselves once in the move to UE4.
We have not been waiting until KH2 for KH3, atleast in regards to development.