Some of the complaints here are nitpicky things that kept me from rating Dinosaur a 14, but most are missing the point.
This is a Disney movie. Disney plots are straightforward, to reach the very very young as well as the rest of us jaded postadolescents. Disney movies have talking animals in them. And Disney characters use contemporary language. Sometimes, they're downright hip. Remember The Jungle Book? Louis Prima in the part of the orangutan, King Louie, singing, "I'm the king of the swingers, ohhhh, the jungle V.I.P." It don't get hipper than that. And Robin Williams' Genie in Aladdin... I mean, if this is your gripe, then you just don't get Disney movies.
Despite what you read about the animation getting old after the first sequence, it never lets down. Disney's Tarzan was complex, but Dinosaur is insanely complex. Plot points depend on shots that demonstrate heretofore impossible techniques. And novel animation touches appear right up to the end. (Anyone who complains about Earl sticking his face in the lens just didn't get that, either).
This is absolutely a must-see--and must-see-again--film.