Because you're telling a story, and I'm sure people fifty years ago would tell the same story differently if they were telling it to you today. Because the time is different. The film is the work of today's audience.
Steven and I have worked together a lot and I'm far ahead of the curve than most people in knowing what he wants, but he knows far more than I know about what's important for the story. So, most of the changes he will make will involve story changes.
What you want to do is, you want to get away from people being afraid to show their work, which is the first thing, because they don't want to be shot down.