Problem with this logic is, the Republicans have shown themselves to be utterly intransigent in the face of almost any Democrat policy whatsoever. Moderate Republicans only exist in the imagination of West Wing-watching Democrats; attempts to be reasonable and compromise have simply served to castrate domestic policy, resulting in well-meaning shambles like Medicare. It's one of the reasons why the system is completely unfit for purpose.
So regardless of who is in charge when the Democrats win again, they have to regain the senate as well in order to have any kind of positive impact. In which case, it may as well be Sanders than some neo-liberal glass of water who treats the working class with complete contempt like Clinton.