I have no doubt that the Tokyo parks-- being able to do whatever they want-- will continue to enjoy new non-IP attractions.
I sincerely hope the IP-only mentality goes away, but I'm afraid it won't until they invest a ton of money into an IP at the exact wrong time and it ends up a flop. I think Star Wars is going to fan the Hooray For IP flames... I can't see this changing in the near future, and I really hope I'm wrong.
I agree Tomorrowland is the best shot, but I can't see Iger or his successor willing to risk their reputations and bonuses on something original. I predict Tron and more Pixar.