When Kingdom Hearts 3 was first announced, fans were immediately excited about the possibility to travel to not just more worlds based on Disney animated features, but worlds based on Marvel Comics and Star Wars as well. Thanks to Disney's acquisitions of Marvel and Lucasfilm, the door was wide open for Kingdom Hearts 3 to explore some truly new territory for the franchise, but instead the game largely sticks to worlds based on Disney and Pixar cartoons. We now know why Star Wars and Marvel weren't included in Kingdom Hearts 3, despite fan demand.
In an interview included in the Kingdom Hearts 3 Ultimania book, a Japan-only release, game director Tetsuya Nomura explained why Marvel and Star Wars aren't included in Kingdom Hearts 3. "[...] in order to change those [properties] into a game, contracts must be made with each company separately, and there are cases where other game companies already have contracts, so although the Disney Group has indeed added those [properties], incorporating them into KH isn't so simple."
This explanation basically boils down to Square Enix needing to work with not just Disney, but Marvel and Lucasfilm themselves to be able to feature Marvel and Star Wars worlds in a Kingdom Hearts game. While it's unclear why this wasn't possible with Marvel, especially considering the fact that Square Enix is working on a high profile Avengers video game, it's understandable why a deal couldn't be made for Star Wars.
For the foreseeable future, Electronic Arts has the exclusive licensing rights to Star Wars video games. Because of the deal between EA and Disney, it would be tricky, if not outright impossible, for Square Enix to add Star Wars worlds to Kingdom Hearts 3. This is unfortunate, but all hope isn't lost.
After all, it's possible that future Kingdom Hearts games could very well include worlds based on Marvel and Star Wars. The licensing deal between EA and Disney will expire eventually, and if EA continues to fumble with the Star Wars license as it's done with the Battlefront games, then Disney may very well choose not to re-sign. This would potentially open the door for Star Wars worlds and characters to appear in a Kingdom Hearts sequel.
It will be at least a few years before the licensing deal between EA and Disney expires, though, so Star Wars fans shouldn't count on any worlds from a galaxy far, far away to appear in any potential Kingdom Hearts 3 DLC. Marvel seems like a more realistic prospect, but even then it still seems like Square Enix would save any Marvel worlds for Kingdom Hearts 4.
Kingdom Hearts 3 is out now for PS4 and Xbox One.
Source: Game Informer