I've been asked this question upwards of a million times, no doubt.....so forgive me if I ramble....a lot of this is personal preference.
MK- Indy speedway needs to go because it stinks (literally), it's huge, and was no fun for me even when I was 8.
Jungle Cruise needs to be moved to AK, the Animatronics just don't cut it anymore.
(And for god's sake I wish they would keep Timekeeper, even if only as a show that they ran hourly or something!)
Epcot- They need a new Body Wars video or something, but I'll still ride it if the line isn't too much.
The entire Land pavilion needs to go in my opinion. I almost wish they had blown that up instead of Horizons, which i dearly miss.
El rio del Tiempo is getting a little cheesy too, and shows an amzing lack of respect for modern Mexican culture.
MGM Studios-I wouldn't mind seeing this stay the same, only I wish they would add a moderately exciting ride to complement ToT and RnRR. I mean, after those two, Star Tours, and Great Movie Ride, my day is pretty much done at MGM
AK-It's been too long since I was there.