Honestly, that is their own fault for not doing the research on what the park has to offer. If I'm going to spend money to bring a 3 year old to a park, I want to make sure it has attraction for him/her to enjoy. I don't blindly spend money without knowing what I'm getting.
Yes, Universal could use some more family friendly attractions, but I don't want them to turn into Disney. What makes Universal special is that isn't a big child's playground like Disney, it has thrilling attractions for people of all ages. Honestly, USF has plenty of attractions kids can enjoy (Shrek, Transformers, Simpsons, MiB, KidZone stuff, T2, DM). If your kid can't handle attractions like these they probably shouldn't be at theme parks anyways. IOA needs a few more family friendly attractions, but outside of the coasters and maybe Ripsaw Falls, nothing is too extreme. That park needs the JP family ride were supposedly getting and that is really about it. Because every other island has something a kid can do (Storm Force and Spidey at Marvel, Popeye ride and ship at lagoon, Hipogriff at HP and obviously all of Seuss).