I am sort of wavering on the film thing. Granted, TB is indeed important to LotR, not to the main plot about the ring, but as a deeper message. Also, TB is fun! For the average movie-goer, one who has not read LotR, TB would have looked like 'excess baggage' at first sight. In the books, he does - as you said, Rhudadlion - a lot more. However, for those interested in TB in the movie, there is a site where you can sign up on the petition for the 'LotR: FotR - Director's cut DVD'. I did.
The site is
http://www.petitiononline.com/LoTRdvd/petition.html.
(This is perhaps strictly movie related, but...)