I don't think so. He is the Jedi who returned in "Return of the Jedi." The family story, such as it was, fairly resolved.

And the trilogy had a cycle. SW a triumph of good over darkness; a counter from the dark side in TESB; and the answer from the side of good.

Yes, had Vader stayed evil, the end of RotJ would certainly have been darker, but I think that would have left it decidedly less fondly remembered.