You should send an e-mail to PJ to ask him why he left out so many stuff from the books and put in so many changes and why he violated the characters, blablablablabla.
Only PJ knows, we can only speculate why our beloved Kiwi did what he did. It doesn't really matter, actually, because the books are impossible to film if you'd follow them to the letter.
Anyway, i think PJ made the adaptation we are all obsessed about because he wanted to make a movie which even tolkien newbies would appreciate, and also a movie which pretty much every member of the family (yes, even Maggie) would be able to watch without too many question marks.
So he put a lot of stuff of the books out and put in a lot of plot/character changes because otherwise ppl wouldn't really get what was happening in the movie. So this is possibly partly the reason why Tom Bombadil isn't in the movies, because most viewers wouldn't get it.
A book which is as complex as LOTR cannot be filmed to the letter, covering every single detail or touching every theme of it. And if someone would try to film it to the letter, we wouldn't have a movie, but a LOTR mini-series. (like with Dune)
PJ just selected from the books what he thought was important, and converted it into a contemporary action/adventure movie for the entire family.
Whether we agree with PJ's adaptation or not, is our call and doesn't really matter. It is a fact that PJ and his crew put an awful lot of work into it and they really did their best to show their vision of JRRT's work. We have to respect that anyhow, whether we like or dislike the movies.
So, i think Tom Bombadil and other stuff was put out because it wouldn't make sense to Tolkien newbies. Good thinking, since it doesn't even make sense to most Tolkienites.
nn[Edited on 7/12/2003 by virumor]
Give up the Halfring, she-elf...