Having recently just taken a vacation to USF with 3 kids 5, 3, and 10 months. There is plenty for kids to do at all 3 parks, but not if your main objective is rides. The 5 year old was able to clear the 40" barrier but we only rode 1 "big kid" ride which was transformers so we could stay together as a family.
We saw shows, met Captain America, Spiderman, spent 80% of our Epic day in HTTYD, experienced different lands, rode a couple lower height requirement rides like one fish two fish, Fyre Drill, and high in the sky. I do wish the main campus had a couple 30" rides of the quality of Fyre Drill, one at each park would be good.
Their target demographic definitely bottoms out at 12 years, but we were able to keep our family well entertained over 3 days.