It seems this is a theme in the Twilight movies, the secondary characters get a lot more attention than the secondary ones. Along the same lines, as I understand it, the "bad vampires" in the first movie just showed up at the end of the book/at the ballgame but in the movie the director/writer had the intercut scenes of the vampires coming towards Forks.
The first book is really funny. HALF the book is about how hot/wonderful/perfect Edward is. Entire paragraphs can be skipped without missing anything. I was amazed that they were actually able to make a movie out of it. The only interesting parts for me were about the vampires. I really think most people wouldn't give this series a second look if Edward and Jacob were just normal dudes instead of monsters.