I think you would need to define the "Disney" audience. Disney's main appeal is that many of us grew up with it so we know the stories and series but it may not necessarily make us a fan. KH only appeals to RPG fans really, as the FF characters are terrible shadows of themselves and barely warrant a mention in the plots of the games. Its the original cast that has real development.

Personally, to appeal more to old school fans, we need either older films or song numbers. Why just let Xemnas speak about his heart? He could have a wonderful musical interlude. In all seriousness, I feel we need to define what a Disney fan is and then we can discuss what they would look for. I myself do like Disney and I actually do enjoy going through the various Disney worlds, the only issue I see is that the Disney characters themselves are static cause most of them are stuck within the constraints of their original films. Aladdin in KH2 was a bit weak cause the cast did not grow. We just got the KH version of the awful Aladdin 2.

I think Winnie the Pooh has been the most successful world cause its the only one that kinda grows and changes from game to game and I like the concept of Sora replacing Christopher Robin in the story. The other Disney worlds haven't fared as well with Little Mermaid rehashing its film plot (which was kinda done in the original game) though I do prefer it in KH2 cause for me, Little Mermaid was always more about the emotions and the music rather than a plot about good and evil so I prefer the campy singing.

Basically, I think they need a better writer ( kick Nojima to the curve and let Watanabe do it instead) and also bring in some people from Disney to help with the Disney worlds as well so we can generate original story content without compromising the original IP.