As I mentioned in a separate post on another thread, my biggest gripe would by far have to be the revamp of Tomorrowland from what I enjoyed during my first visits in the '70s. Take away the geeky dark colors and bring back the white and light blue theming and the waterfalls at the entrance, and yank out those gawd-awful Astro Orbiters and bring back the sleek Apollo StarJets, and all would be right with that part of the World, as far as I'm concerned.

P.S. And while they were at it, a close second and third would be to bring back If You Had Wings and also to restore the Carousel of Progress with the RIGHT music - "Now Is The Time!"