I've said this somewhere in this thread but I'll say it again. The best thing Universal can do, IMO, is to take an IP that isn't aimed directly at kids to anchor KidZone with. Aside from Spongebob, what could they realistically use that would be timeless enough to make their investment worthwhile? Kid's properties aren't meant to last, they're meant to sell tickets in a movie theatre, sell some merchandise, and then be forgotten so the studio can move along and do the same thing with another movie a few months down the road. Occasionally you get smash hits like Shrek and Despicable Me but those come few and far between, and since both of those are essentially out of the question, there must not be much Universal is seriously considering right now for KidZone.
But let's take a look at more adult-oriented properties. PG-13 movies sell more tickets, benefit from more promotion, and therefore have better opportunities to become franchises worthy of transferring over to a theme park. It would be crazy to make children's rides out of properties not aimed at children though, right? Well, let's look at it this way. The park's most popular rides among kids (aside from Despicable Me) is generally Transformers, Men in Black, and the Simpsons. All of which stem from PG-13 franchises. Even look at Disney's most popular rides. Pirates of the Caribbean and the Haunted Mansion, two of the most successful "family" rides ever created, gave birth to movies aimed at a more mature crowd than Dora the Explorer and Spongebob. Finally, take a look at what the hottest IP right now, Marvel, and check out who its target demographic is for merchandise...kid boys. Despite The Avengers being PG-13, what little superhero fans actually didn't go see the movie? My son has been watching superhero movies since he was in 2nd grade. The point is, a property does not have to be a cartoon to be kid-friendly.
So what does this mean for KidZone? Right now you've got ET, Barney, and Curious George. They're kid-centric properties all right, but they are a lot less relevant than the franchises you see now that are aimed at an older crowd. So why would Universal waste their time trying to find the next Despicable Me in a hugely and purposefully over-saturated market? Replicating that success is hard, and predicting it in a time-effective manner to build a theme park attraction is even harder. It seems to me that the smarter move would be to abolish the idea of a KIDzone altogether.
For one thing, KIDzone is discriminating. Universal gets flack for having rides aimed mainly towards an older crowd, but having rides aimed mainly at a younger crowd is just as bad. KIDzone is a turn-off. That land needs to be filled with rides like ET, stuff that everyone can enjoy...not just people over 40" and not just kids under 4 years old. In any case, it's already been established that more little stuff like Kang & Kodos will be placed around the park in the future, so let that keep going. There's no rule saying a ride has to be for toddlers OR the rest of the family.
So after that whole idea and theme has been dropped, I'd say Universal should not so much worry about the IP, but more the actual attraction itself. Pirates and haunted houses aren't "kid-friendly" by definition, yet they've yielded some pretty successful family attractions. Universal can apply those same principles of creating an inviting attraction with whatever they've got to work with. And it doesn't have to be a hot property...Men in Black is past its prime but shooting aliens is a pretty timeless/enjoyable theme. As long as the attraction lacks intensity and is generally mild in nature it can be a successful family attraction regardless of what it's based on. I mean, obviously zombies and serial killers don't work, but the Hollywood franchise machine has given theme parks a lot of material to work with. I feel like Universal is wasting their time trying to nab the next hot kid's franchise because kid franchises aren't meant to stick around very long, they're barely meant to outlast a normal kid's attention span. What they should do, in my very humble opinion, is start looking at the right attraction, and then worry about the right theme to go with it, G-rated cartoon or not.