I think they can keep Tomorrowland relevant with Tomorrowland theming. An attraction has an approximate lifespan of 10-15 years without major overhaul and Refurb. That should allow for appropriate change over of Tomorrowland attractions or updating as needed.
For example, Space Mountain just needs updating, Buzz Lightyear is good into the future, etc. Anything space related has staying power because we're not close to space travel as a normal life activity.
Its not Pixar that bothers me, its Monsters Inc. is in the wrong place, its Carousel of Progress doesn't get the love it deserves (thought I could be convinced that maintaining this original attraction is appropriate), Stitch was just a bad replacement for Alien Encounter.
They could easily theme appropriately with or without Pixar. Meet the Robinson's seems like an easy way to go for a new attraction. Though, I could be convinced they belong in Animal Kingdom in Dinoland (I have a big head and little arms...
I love T-Rex).
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