Tim here. The Good Dinosaur is, in the first place, a kids' film: not a film about kids but also somewhat for adults, like Inside Out. Or, indeed, most of what Pixar Animation Studios has produced in its 20 years of making features. In fact, even including the unabashed toy commercials of the Cars franchise, this might be the most unmixed "for the kids" movie out of the 16 films of the Pixar canon. This has translated into a lot of disappointment from a lot of people openly hoping for another film at the Inside Out level of emotional sophistication and narrative creativity, which was really never going to be in the cards; frankly, the movie doesn't seem to have any designs on that kind of sophistication.
Still, it's easy to be too harsh on the movie: simple and direct as The Good Dinosaur certainly is, it's an enormously strong version of its stock narrative.