A problem that Square Enix has encountered in the past has evidently been a learning experience for them. Square Enix are eschewing the use of internally developed tech and shifting the development of the upcoming Kingdom Hearts 3 to the heavily supported (and very powerful) Unreal Engine 4.
Speaking to Famitsu (translation via Gematsu) the games director Tetsuya Nomura said, “Surely and steadily, we’re progressing on schedule. For various reasons, we’ve changed the game engine to Unreal Engine 4, because of which we’ve been facing rendering troubles. But Epic Games has been really cooperative and helpful, so we’re progressing just fine.”
This however only goes to show that the game isn’t as far into development as some of you Disney/Square Enix cross over fans may like. This is further supported by Nomura saying they are currently work on “scenario writing and world selection”. Stay tuned for more information on the game in the coming months.