It's wrong to think that either company needs to do something to appeal to a broader audience. Both Disney and Universal are positioned exactly where they need to be. Disney is magic and fantasy. Universal is action and adventure. There are exceptions at each to help round out your day, but generally that's the game plan.
Back to the topic of future projects, parks specifically, I would like to see Universal do something to evolve the theme park experience. And by "theme park experience", I mean going through a turnstile and then waiting in line for rides. I think that whole process is ready for a rethink.
I would envision some type of boutique (read: smaller) park experience where you are 110% immersed, and possibly have a mission to accomplish. So, Diagon Alley theming, but a mini-park, where everyone you encounter is a character and there are a limited number of guests in the park (no more than 5,000). I have no idea what this is. Maybe a Jurassic World, or a Hunger Games, or some type of haunted experience, or something. I know a while back the idea for a LOST island was tossed about, where you were on an actual island at Disney World and had to figure a way out -- something like that. MYST in real life, if you will. It doesn't even have to be around an existing IP, it can be an experience of its own. This experience would not be for everybody, it would come at a premium price, and it would be highly in demand (waiting list!). The experience could even start weeks before your vacation, as you begin receiving stuff in the mail (e.g. a message in a bottle asking for help) at your home, gradually enveloping you into the story. Truly a once-in-a-lifetime experience.