The problem with tolkiens characters is that they are not realist in every sense. All the traits are real (love, hate, concern, bumbling, nobel, etc), but some traits possesed by them are not consistant with others. This works fine in the book, but in a movie they would look too fancifull. Especially in a movie where the realism detail is very good (costumes,
swords, etc). The characters have to be as realistic and believable.
How comical was the character "Sir Robin" in The Holy Grail. He is a Knight, denotes nobility, courage and the like, yet he runs away from a battle. The two traits just don't work together, except for comedy.
In the book,
sam (just for an example), is both a bumbling boob, an innocent soul, and a nobel friend. If PJ were to film him this way, his character would be wholey unbelivable. The way Sam is presented in the movie is different than the book, but he is totally believable in the movie.
The converse is true also. If sam were written in the book the way he was in the movie, he'd be a less effective character than Tolkiens sam.
People keep complaining about movies being interested in the special effects. Well, thats why movies were invented. If just reading the book was enough, why start making movies? So, don't blame PJ for using the medium to it's fullest extent and doing a good job. Movies are movies and
books are books. The eye and brain process information in a different way when you don't have to use your imagination to create the scenery etc like you do in a book. This is why character details are less problematic for writers. They've got tons of room and time to hide the incosistancies. When a writer writes the word "blue", your brain has to process blue. Then apply "blue" to whatever he is discribing. In a movie, the blue sky is automatically processed, along with every other discriptive explanation in the book, freeing the mind up to be critical of other things. IE, cartoonish characters in a serious story about good and
evil. It just don't work.