And Banjo-Kazooie is owned by Nintendo's direct competitor. And yet, that happened!
Disney is willing to put Mickey Mouse in a weird crossover anime video game; I don't think putting a character exclusive to that video game in a different crossover game would somehow be a bridge too far. Do you really think Disney is going to hold Sora more sacred than Mickey Mouse?
It's pretty bizarre to say "Sora is Disney, next" and just shut down that discussion in a world where Kingdom Hearts, y'know, exists. (And is pretty popular, to boot.)
The problem I'm seeing is the "Goku and Iron Man" rule.
Like, yeah, Sora's a video game character. Kingdom Hearts is half Final Fantasy. It has its own video game characters, yeah. But be honest with me for a minute: do you really want Sora without Donald & Goofy? Because Kingdom Hearts identity is tightly interwoven with Disney's characters. I wouldn't rule it out as
impossible, with how this roster has been turning out, and I'd be down to see Sora show up (I could reactions to him being INSANE, I know a lot of people want him). But, at the end of the day, I keep thinking about Sakurai's feelings about non-video game characters, and I can't imagine Sora showing up without these non-Video Game characters.
Disney wouldn't be the obstacle here, the nature of its characters is. It would need Sakurai to open up the door to even MORE harassment from people who want Goku, because he'd be breaking the one barrier to entry to
that character: that he didn't originate in a video game. I don't think you'd do Sora justice without the Disney aspect of his series being represented, and I just don't know if Sakurai will do that. I may exaggerating here but you get the idea.
It's not impossible, there's a lot you could do for a moveset for him, but he'd feel incomplete.