I don't think a unique, immersive attraction that merges thrills with story necessary needs to be tied to an IP? It obviously can be (Splash Mountain is a perfect example of this), but I'm talking about competition on the basis of ride technology, not theming. I think another important point to make here is that both Universal and Disney have made recent attempts at immersive thrill rides (7DMT, Expedition Everest in A-Mode and Journey to the Center of the Earth from Disney, Gringotts over at Universal), this isn't a concept exclusive to Universal. And I think if Disney were to really embrace adding multiple dark-ride scenes to a coaster, it could easily outperform Gringotts, and maybe even Revenge of the Mummy, in a way that's unique, inventive and true to the spirit of Disney. Very few ideas are 100% unique, it's all in the execution.
That aside, I still fall somewhere in the middle on IPs. Obviously I agree that Iger has leaned on IPs to a ridiculous extent, but I don't think IP-based rides are inherently uncreative, or that these kinds of efforts should be abandoned completely! I think there's a place for IP-based lands at the parks. Universal may have started the trend, but Disney has put its own spin on this & will continue to. I'd love to see more original rides (especially dark-rides) going forward, but don't begrudge the addition of IP-based rides like MMRR that promise to push the envelope and bring something new to the table. GOTG...is another story.