Well, I don't know about that. A story that sticks in my head is waaaaay back, Peter Jackson giving Arwen so much prominence and when asked about the Arwen/Aragorn garden bridge scene (not in book etc.) he said "because he thought it would be nice". Then there's directors like Michael Bay.
Just sayin' sometimes I get the feeling on set that directors ARE questioned and argued with. Like Marvel arguing with Whedon over the Ultron farmhouse scene. But directors "win" (at times) and get to "realize their vision" whether it works or not. Not sure at times if directors really CARE about the questions/problems. They go ahead and do stuff anyway. I guess they feel like otherwise they'd never get anything done.