That is an interesting perspective. I think the importance of Vader’s redemption rests on the father/son dynamic, and I don’t know if a political motivation would have resonated with people on the same level as what we got.
I think it would’ve been possible to channel one through the other, have Vader’s dying for Luke only a component of a larger sacrifice for the greater good. It would’ve taken a better script than the one we got, or at least better direction.