When the MK opened in '71, this theater
housed the Mickey Mouse Review, an Audio-Animatronics musical review featuring Mickey, Minnie, Donald, Goofy, and many of the other Disney animated short characters. Interestingly, this is the only time these characters have been portrayed in animatronics.
In, I believe, the late 70's Disney shipped the entire show to
Disneyland Japan, where it still runs (they felt that they needed another attraction to open with the park and had no time to build one). The theater in Florida sat dark for a while, and eventually received Magic Journeys after Captain EOS opened in Epcot. (Magic Journeys, by the way, gave me the creeps. I featured a clown, and I hate clowns).
After another dark period, The legend of the Lion King took over the building, and it ran for a few years.