Sorry, didn't get back to this.
The thing is it's all about the archetypal battle between good and evil, so both are (albiet not entirely realistically) clearly dileneated.
Although Darth Vader was beset by the moral conflict between the two, and went to the dark side for the sake of what he thought was good. So he tread the grey in between, granted haphazardly. Hence, he did encompass what you say in a way. Not behind the scenes, orchestrating, but at the forefront as the the chief agent of it.
Plus the average movie fan, like most people, is not prone to indulging such scenarios. A two dimensional myopic world view is difficult enough for folks to consider,,,