Universal Studios AP include IOA. I do not know of any single-park AP, so you pay for it either way.
However, IOA has many things to offer aside from the "fast rides." They have some great water rides and Spiderman is an awesome simulator. The scenery is an experience in its own.
Universal has seasonal fireworks and parades. I'm not sure exactly when they usually do these, so I might leave some things out, but I'm sure DM can help me. Universal does parades for Mardi Gras and has the Macy's Holiday Parade. Fireworks also occur around Christmas time and Summer time.
Each parks has its characters. Kids can meet Jimmy Neutron, Spongebob, Scooby and Shaggy, Fred and Wilma Flintstone, Spiderman, Cat in the Hat, Thing 1, Thing 2, etc, etc.
Also, Universal has shows. I'm not familiar with the shows at Disney, because I haven't been in a few years (with exception to NOJ...but I only saw concerts). Universal has quite a few shows: Horror Makeup Show (PG-13), Beetlejuice Graveyard Revue (PG-13), Extreme Ghostbusters, Blues Brothers, Street Breaks, Animal Planet Live, and a couple other kid-geared shows.