Having played Kingdom Hearts games myself and now my children playing the games my family would love Kingdom Hearts Characters in the park. But I agree that Disney would have to make a movie to get KH more mainstream before they would do it.
I agree; Disney should absolutely consider adding KH-related stuff to the parks.
I know there are Star Wars Weekends, so I don't see any reason why Disney shouldn't do a similar thing for Kingdom Hearts. I'm sure many people (especially fanboys :P) would love see characters from KH, or maybe even the older Final Fantasy games, in the parks.