Kingdom Hearts co-director and game designer Tai Yasue said in a December 1st interview in London with Kotaku that Marvel and Star Wars themed worlds are "not off limits" to the third installment of the Kingdom Hearts series.
Since Kingdom Hearts 2, released in 2005, Disney acquired both Marvel and rights to Star Wars. With full backing from Disney, the possibility for Marvel and Star Wars worlds opened up.
“Yeah, I can’t go into specifics, but there’s a lot of new Disney stuff and we have our plates full,” said Yasue. “There's a lot to consider - we’re looking at all of Disney, the new ones as well, they have a lot of pull and draw.
“We have to come up with a world that has a lot of originality. We want variety in our new Kingdom Hearts, so we don’t want too many of one sort of world, that would look the same. For each world there has to be some meaning for it, in the plot; in Birth By Sleep, for instance, in the Cinderella scene, the characters learn something specific by relating to Cinderella. Also, gameplay-wise, is that world something that would make gameplay fun? There’s a lot I can’t say, but there’s so much to consider."
The reporter then asked if she could safely infer the that Star Wars and Marvel were not off - limits, Yasue stated their potential for consideration.
“Well, yeah. They’re all under consideration,” he said. “Nothing’s off-limits, we’re considering all of the worlds. There are so many wonderful concepts. We’re happy about that, but at the same time it’s really tough to choose."
Many options could still be on the table with the game release date still TBA. Maybe we'll get to see Sora fighting Ultron, or Riku wielding that, um, 'unique' claymore lightsaber from the new trailer for Star Wars The Force Awakens.