I don't think the third film was bad, i think it is still an awesome movie, but it wasn't as good as the others. Here are the reason why I dislike Jurassic Park 3 more than the other films.
1. The Spinosaurus, for reason which are obvious. Well while I agree the Spinosaurus was shoved in our face, it was just like the T-rex in The Lost World, no?
2. There was no Carnotaurus. that was a disappointment to a lot of the novel fans who thought that if they didn't put one in The Lost World, they'd put it in the third film That's silly, you shouldn't hate a movie just because it didn't have what you wanted
3. The shortness. It was short, and it could have had a lot of cool scenes if they made it a little more longer Hmm...you have a point there, but I prefer short to boring like TLW was
4. The velociraptors. Most people don't like the Raptors because they're too smart and the fact that the raptors look totally different from the fist two films. Firstly, the raptors were BARELY in 2, but you still do have a point. Ah well, not that big of a deal. Secondly I love the velociraptors, especially because they're smart. That's what makes them so unique!
5. The Pterosaurs were a problem. They had teeth. Pterosaurs means "no-toothed lizard." It doesn't make sense. The other problem is that we see a Pterosaur at the end of The Lost World thats roaming free, but the Pterosaurs in JP3 were trapped in they're aviary. Woah, really, I did not notice the Pterosaur in #3. Hmm...but I still like it, especially the part where they realized they were in a cage, and then the Pterosaur stepped out of the fog and abducted the kid. That was cool
6. The plot. people thought it was too small. it should've had a more complicated plot that should have involved Lewis Dodgson and the company BioSyn. Refer to my comment on #2]