To enjoy this movie, you have to take it for what it is. I used to wonder if Disney were going to make a movie about dinosaurs and when they did, it wasn't a bad choice to combine GGI characters with real backgrounds.
I was impressed by the trailer and when I finally saw "Dinosaur" first time, I liked some parts, but overall I found the movie a little mediocre. Seeing it for the second time, I appreciated and liked it more, so, once again: you've got to take it for what it is to really enjoy it.
The visuals is absolutely the big highlight of the film, especially combined with the beautiful and (in my opinion) quirky score of James Newton Howard. The characters are quite all right too (especially Aladar, Zini and Eema), although the film focuses more to move the plot forward. The only character I don't like is Kron. He's so straight forward and narrow-minded that he gets just uninteresting.
I was never a fan of "The Land Before Time" (in fact I hated that movie), who has many similarities to "Dinosaur". Like most of us know, the story is unoriginal and (as expected) comes with the usual Disney moral. But the real problem with this film is that it seems like the directors and screenwriters disagreed for which audience this movie would fit too (although it was rated PG). For kids it could be too scary (especially the Carnotaurs, not that I'm a coward, *laughing*) and for the older viewers some parts may be too childish.
Like other Disney films, "Dinosaur" has some tender moments (for those who like romance, there's some of that, too), but the film it self is not too sugar-coated, it's surprisingly straight-forward and serious. There are some comical lines that makes you chuckle, but without sacrificing the integrity of the film. The first act, which shows Aladar's arrival at the lemurs, is actually portrayed in a different, more detailed way than Tarzan's arrival at the apes, which is refreshing to see.
Overall, this is not a perfect movie, but it has some great moments, so I like it