The environments in The Good Dinosaur were stunning....and then the characters were less so. It's like they were designed by two completely different studios.
Pixar really wants to stay out of the uncanny valley with their characters, so they intentionally design them to look "cartoony"--closer to the classic hand-drawn animation of the past. They want their movies to look like animated movies.
"Live action" movies try to make it to the other side of the uncanny valley. Usually the most successful efforts cheat a bit by avoiding human characters. Think Avatar, Gollum, Snoke, Thanoes, etc. They look so real! (If aliens or ring-wracked wretches were real...)
Where movies looks weird is when there are elements on both sides of the uncanny valley--in the case of The Good Dinosaur, the backgrounds look real and the characters look like cartoons.
This was surprising because Pixar is usually careful to avoid this. The sea in Finding Nemo looked amazing, but it didn't really look 100% real--it looked like a beautiful stylized version of a sea. Same with the environments in The Incredibles, as the top blog here details.
Good Dinosaur and Up are both interesting cases of Pixar's environment team exploring if they could use Google Earth (and equivalents) for location scouting, to the point where Good Dinosaur used a lot of direct satellite imagery and terrain data to bootstrap the animation process. Which is fascinating technically, but absolutely an interesting comparison to the less realistic approaches of everything else in the film. Up they managed it quite well because the real place they found as example is fantastic enough to support the rest of the film and the pulp adventure storyline supported that uncanny valley realism; The Good Dinosaur did not find something fantastic enough nor did it really support the story near as well.
I think The Good Dinosaur was one where the directors and writers got removed and replaced during production. Might have been due to the vision changing.
Inb4 “darned execs”: Pixar did basically the same with Toy Story 2, throwing out 90% of the movie with barely a year to go before release date, and it worked out. Sometimes reworking it is the right thing to do.
