I have really enjoyed playing both of the KH games, but I was wondering if KH would have been better without Disney and Final Fantasy characters. I know that they were important aspects of the game, but some of the Disney worlds felt like a waste of time. And even though I really liked to fight along side or fight with some of my favorite FF characters, they weren't really needed. I guess what I am trying to ask is if you think the game would be better only using all original characters (like Sora, Kairi, and Riku) and worlds replacing the Disney and FF ones.
If we replace the Disney and FF characters and world, then it'll totally be a whole new game, environment, and storyline. 
. Disney is the crux of Kingdom Hearts (more so with KH than KHII, however), whereas the Final Fantasy characters are the proverbial icing on the cake. Basically, I imagine it was a ploy to draw Square's FF fans to the franchise, but it worked amazingly well regardless.