I'm really excited for the Tower of Terror changes, mainly the posibility of a unique projection lighting package. (I can only hope.)
Toy Story Midway Mania has to be getting some sort of update. With Toy Story 3, it's the perfect time for it. I think California would also get the update.
Rock n' Roller Coaster is probably getting just a clean-up, but a more permanent queue-less wait system could also be done. From seeing it in action when they did the test a few months ago, it seemed to work well once you get past the initial confusion of the change. If you wanted to sit and do nothing and wait on a wall, you could, otherwise, there was a DJ you could dance to, video games to play, and of course snacks to eat from The Rock Station (for a price). As far as dropping Aerosmith, I'd be sad, but I know eventually some day it would probably happen. My guess is that day will come later in the future with a vehicle upgrade to be able to do something similar to the Hollywood Rip, Ride, Rock-it at Universal where you can pick your own soundtrack. I could see the ride featuring multiple choices to please everyone's tastes. Of course, alternate replacements I'd love to also see would be Red Hot Chili Peppers or No Doubt.
This summer, Studios is probably going to be similar to what is currently being offered this week and last week. Nightly Fantasmics, multiple performances of Mulch, Sweat, and Shears near the hat, Citizens of Hollywood (and possibly Citizens of New York?), more showtimes, atmosphere, and nightlife.