There are several that I thought were highly over-rated:
1. TT: The most over-rated ride ever. If you're a child, than you MIGHT find this ride scary. I live in California...people drive like crap all the time.
2. HISTA: Extremely outdated and the CM don't even enjoy working at this attraction.
3. Soarin': Rode it numerous times at DCA and this ride/attraction is extremely over rated. It's okay, but not great. I wouldn't mind riding this attraction if it were a ten minute wait for it.
4. Buzzlight Year: Boring. It's a moving carnival attraction. Nothing special about this attraction. Too bad, because they could have done so much with it.
5. Backstage Lot Tour: If you have two to three hours to waist your life away than check this attraction out. The backstage stuff is boring, nothing that is impressive, and more the half the sets/costumes/props/etc. are from movies that stunk at the box office.
6. Stitch's Great Escape: Never ridden it and probably won't. He doesn't appeal to me.
7. Dinorama USA: This entire section is poorly done. I know it's suppose to feel like a nice carnival and the classic cars in the "parking lot" just feels like Disney didn't know what else to do so they choose this theme as a last minute suggestion to put down on paper. Which, I can't stand DINOSAUR. The ride is basically like The Indiana Jones Ride at DLR but without a decent plot or anything that would make the ride entertaining.
I'm sure there are more things I could write down...I just cannot think of any at the time.