In the games that come in the future after Kingdom Hearts III, do you think Sora will still visit more Disney worlds and maybe Pixar worlds. There are so many great Disney films. Nomura won't be able to fit all the best ones into Kingdom Hearts 3 alone, they would need more side games in the future to fit more of them in. Do you think I'm right?

Even if Nomura used every Disney Property under the sun he can still make original worlds and put a spin on the older worlds to give the feeling of a new experience also he can use specific locations in each Disney and Pixar property, so to answer your question No they won't need more side games because of DLC

There will always be Disney worlds. It's Disney's game.

Disney made this Game of Course i'm sure there's going to be More Disney Worlds in Kingdom Hearts III and the Next Saga of course they'll have more Disney Worlds in the Next Saga after III gives more new Disney Worlds to show since Toy Story might be appearing in Kingdom Hearts III.