I really didn't like what they did to Faramir. Apparently, from what was said in some of the "making of" documentaries, they felt that his character needed to seen to grow, so they didn't like that he was so good to begin with and they made him weaker.
I fail to see why that was at *all* necessary.
JRR Tolkien said in an interview (I read it long ago, couldn't give you the source) that Faramir was the character most like him. I didn't like the film actor much either. In the book Faramir resembles Aragoron more. He's a Ranger not the wimpy sniveling whiney interpretation Peter Jackson went with.