You have to accept that the moment you hand a script to a director, even if you've written it as an original script, it becomes his or her movie. That's the way it has to be because the pressures on a director are so staggering and overwhelming that if he or she doesn't have that sort of level of decision making ability, that sort of free reign, the movie simply won't get done. It won't have a vision behind it. It may not be your vision as a screenwriter, but at least it will have a vision.