Ah crud, I missed it...
I've gotta ask, why do people insist on using this as if it's a genuine argument? I mean, honestly, even ignoring the fact that Sora's a Disney character himself or ignoring that the Kingdom Key actually addressing this issue, why is this such a fixation? He's made cameos in other games without other Disney characters (unless you count Riku) with little issue from Disney AND fans, we all know Sakurai has expressed not wanting to put in non gaming characters into the game, and to top it all off Kingdom Hearts has enough of its own identity to represent itself without the use of characters like Mickey, Donald, Goofy, ect.
Every time I see or hear this argument, I can't help but think that it's just an arbitrary excuse people use just so they can say that Sora isn't happening. It doesn't help that I never get an answer when I bring this stuff up with anybody. So I'll ask you, Why? What makes you think the kind of characters that Sakurai doesn't want in smash bros. are needed in order to properly represent Kingdom Hearts? Why they're needed here when they weren't ever needed any other time Sora made a cameo appearance. And why the likes of Riku, Kairi, Or the Organization aren't enough to properly represent the series they were created in?