There is a new interview online where Tom Felton discusses a bunch of things.

Q. In a lot of films, the bully character just picks on the protagonist and doesn’t really have a lot of back story. That’s not the case in the new movie.
A. One of the beautiful bits of the story is that Draco is rather weak; he hasn’t got the courage of Harry, he’s not as strong as Harry and he’s desperate to prove himself. He wants to be the Chosen One and he gets his opportunity to be chosen, but he’s chosen by the bad guy. By the end of it, we show a completely different side of him.