LEGO and PIXAR just signed an agreement: Disney, Lego strike licensing deal - Orlando Business Journal:
So if GM does pull out of Test Track, and Disney looked to re-theme the attraction, Cars is a no-brainer for brand recognition (the ramifications to Epcot's theme are another matter).
So if they went with Cars, what if the Epcot version were "LEGO" Cars rather than pseudo-realistic ones? I can see an easy sell to the theme park guys - the immense amount of toy sales in the gift shop after the ride would see to that.
But what would fan reaction be?
Personally, I'd be happy because:
1. I don't like the automotive testing theme as it stands now, and the "crash test dummies" are horribly 1990s, so anything is better
2. Cars is a fine Disney movie
3. Having a LEGO version of Carsland would give Epcot some distinctive flavor over DCA (and vice versa)
I'd be dismayed because:
1. it's further Pixarification, cartoonization, and move away from "hopeful futurism" that characterized 1982 EPCOT Center.
2. LEGO versions of cars would be even more kid-like, and not match the adult vibe of Epcot (come to think of it, this may be a positive for the execs, since Epcot sometimes tests low for families with small kids)
On balance, I'd be OK with it. The current Test Track is off-theme already, so might as well be off-theme but within the Disney universe.