I like LBT1 more because it was the first LBT movie I saw. I was born in 1985 and I saw LBT probably the first year it came out, when I would have been 3 years old. And the first sequel didn't come out until 1994. So I would have been about 9 years old, and before then I would have known about LBT1 for about 6 years before any sequel came out.
When I was younger, I did love the sequels as much as the original. But overtime I started to prefer the original. As I got older, I realized how much the sequels changed LBT. From the very first one, the tone is completely different, more kid-friendly and less epic than the first movie.
The one thing I came to dislike about the sequels (besides the singing) is the Great Valley. In the first movie, the Great Valley was only supposed to be a place where plants were abundant and they could eat there forever pretty much. But in the sequels, it was changed to a safe haven from sharpteeth. This change I felt ruined the Great Valley. It makes little sense for something as big as a longneck to get through just fine, but not sharpteeth.
I'm pretty sure in the book version, the first sharptooth was supposed to try to get into the valley and he was almost successful; he only failed because Littlefoot and the others distracted him. He may have been doing the same thing in the first movie, looking for the path into the valley cause he smelled prey.
By saying that sharpteeth can't into the valley, they add an illogical barrier to the franchise right afterwards. I don't feel that was the smartest move on the directors' part. And another change that I dislike just as much is saying that sharpteeth were stupid, and then making them out to be stupid. If the sharpteeth were really that dumb, I'm surprised they even live long enough into adulthood; I would have expected they would have died from doing something stupid like sticking their heads into a tarpit because they saw movement and thought it was a meal.