When my son was 5 and daughter was 12 we went to US for 2 years in a row. My kids choices are in this order: #1 Disney Waterparks, #2 Universal Studios, #3 Disney themeparks, #4 Seaworld.
There was plenty to do for everyone. The Spiderman 3D virtual ride is awesome for the entire family. The Bluto Barge raft ride is similar to Kali River Rapids at Animal Kingdom. Shrek 4D is also a fun family show (similar to Philharmagic at MK). Jimmy Neutron 3D ride is fun. There is a Woody Woodpecker roller coaster that is very similar to Goofy's Barnstormer at MK. They have a Dr. Seuss ride similar to Dumbo. There is a Cat in the Hat sofa ride that is fun for everyone. There is also a Magic Unicorn roller coaster (1 step above Goofy's barnstormer). The Jurassic Park ride is a water boat ride, with 1 drop at the end (less of a drop than Splash Mt.), but the dinosaurs inside scared my son a little. The Pteradactyl Flyers are for kids only (adults must be accompanied by kids under a certain height). I haven't rode those, but they look like fun, you look like you are in a hang glider soaring over the park. There is an entire Curious George water fun area for kids of all ages. The ET ride is fun, a little dark, but no fast drops or anything.
I hate scary rides and still felt like there was plenty for me to do, along with both of the kids. Just like Disney there really is something for everyone.
Next year our trip will consist of only Waterparks and Universal!