My husband & I did Universal back in 2012. We got a 3-day park hopper pass & spent one day in each park, saving the 3rd day for the park we loved the best (the one with HARRY POTTER!!).
My hubby does NOT like big coasters, & there was still a ton of stuff to do, see & ride at both Universal parks. Some of the attractions are definitely worth waiting in line to do more than once - especially Men In Black & Spiderman - interactive rides w/o the big coaster action. There are shows that are wonderful too - Poseidon's Fury, & the Hollywood Horror Makeup show.
In Harry Potter, the Hogwarts castle ride (like riding the broomsticks) is amazing. Be smart, go in the line for single riders. It's not like you can talk to each other when the ride is going, & you'll all get done w/in a minute or so of each other. The line is 1/2 to 1/4 the wait - we went back two more times in the same amount it said we would have to wait to ride together.
Hope you have a blast! T. :)