I can hear the sound of William Goldman laughing at someone saying how powerful a writer is in movies.

I think a good script is the most important thing but I think a director has the final say of what goes up on the screen. Filmmaking is a laborious task and a director doesn't shoot what he doesn't want to shoot. I also think most directors would take advantage of Ron's comedic skills and Emma's star quality to liven a scene.

Another thing, one of a screenwriter's main priorities is to write to an actor's particular strengths. Tom Mankiewicz, who wrote a few of the James Bond movies, said he wrote the character differently when Roger Moore took over from Sean Connery. There were things Sean could say and do but wouldn't be right for Roger and vice versa. I think over time Dan, Rupert and Emma each developed at their own pace as actors. Ron definitely got great as a dramatic actor recently and the script of the latest movie reflects that. The scene where Ron talks Harry out of leaving is a really great scene that wasn't in the book.