I would have loved to have seen Disney's America built, mainly because it would have been built close to my home and I probably would have visited it every summer unlike WDW where I go every three or four years. I liked how it was a unique concept and it would have created a resort that was different from the other two located in the states. People would still visit WDW in addition to Disney's America because they would have offered totally different things. Unfortunately it is probably dead and a unique resort without a Castle Park will not be coming to the US.
I could see them building some more DVC resorts with their own mini water parks like Aulani. Perhaps a ski resort ala Mineral King.
Disney has designed such great water parks and from what I can tell they are loads cheaper than building a full theme park. It would be awesome if they expanded the water park concept and built like two more of them around the country. Perhaps on on Long Island near NYC or in the Poconos/Lake George region and maybe another one in Hawaii or Virginia. If they do this it cannot build its own tourist following like at WDW but rather it needs to be built where there is already a large tourist base such as NYC or Washington.
When they were considering building the Disney MGM Studios Backlot in Burbank, there were plans to build similair entertainment centers in cities all around the country themed to the historical background of the cities. It would have basically been a themed Downtown Disney with a hotel and a couple of attractions.