Disney already did their CGI verson of Land Before Time called Dinosaurs back in 2000, because at the end of the movie. They were living in something that looked a little like the great valley.
Dinosaur IS pretty much a rip off of LBT. If you compare the text on the back of the cover of both movies, they're pretty much identical. For example:
LBT: "...a young bracheosaurus named Littlefoot suddenly finds himself on his own..."
Dinosaur: "...
Dinosaur tells the compelling story of an iguanodon named Aladar, who is separated from his own kind..."
LBT: "Setting out to fin the lush feeding grounds of the legendary Great Valley..."
Dinosaur: "...Aladar and his family follow a herd of dinosaurs heading for the safety of the 'nesting grounds'..."
Disney pretty much just stole the major plot elements of LBT for Dinosaur. Even though Dinosaur may be a ripoff of LBT, i still like it, but it doesn't even compare to LBT in my opinion.