I've always thought that The Wizard of Oz section in The Great Movie Ride was a waste of a potential major draw. While the majority of the movies in the GMR would have trouble carrying a whole attraction on their own, the Wizard of Oz is a beloved by generation after generation, has a variety of a colorful scenes, recognizable characters, and lots of songs. I can't understand why, having presumably paid for the theme park rights, Disney didn't give the Wizard of Oz a full-blown attraction of its own.
Not that it's too late, of course. I doubt they ever would, but I think it would be a great idea to replace the big Oz scene in GMR (we can discuss with that elsewhere), and give the Wizard of Oz a dark ride all of its own.
Heck, with all Oz has to offer, it could practically sustain it's own land, attractions, eateries, meet-and-greets and all.