These parks have very short memories.
Reservation systems have also been tried at (at least) AstroWorld and Kings Dominion. My understanding is that as of yet, none of the reservation systems other than Disney's FASTPASS has had the desired effect, and all of them...including FASTPASS...have managed to aggravate customers.
The only thing a park can do that will actually work is to keep the lines moving. Keep the intervals down, and that will keep the capacity up. Keep the capacity up, and the lines get short. It's that simple.
--Dave Althoff, Jr.