Disney's America would ahve been perfect in Disneyland. If it were built in WDW, well, you all went over the problems of a 5th park right now. Plus, I think there enough America/patriotic things all over WDW, in Liberty Square, Frontierland, Main Street, and of course, the American Adventure.
At Disneyland, they could use the American Adventure, or a similar show as a centerpiece, and it would be a very educational park. Yes, we all go to parks to have fun, but it would be nice to see Diney try something different for a change. Walt always wanted areas like Frontierland and Main Street USA to be very historically accurate, so as to educate as well as entertain.
But ambey thats why he chose to recreate those eras of America, instead of the ones from War Time? Still, it would be interesting to see the Imagineers take on a serious recreation of a War Period (excluding Sunset Boulevard's 1930's WW2 theming).