Robert Maxwell wrote:
Even if Walt single-handedly saved a bus full of schoolchildren from radioactive zombie vampire child molesters from Mars and then died after rescuing the last child (perhaps at the hands/fangs of one of said RZVCMs), it wouldn't redeem him, it would just tip the scales ever so slightly away from all the horrible, horrible things he's done. He's not a hero, and he never was. Trying to turn him into one at the last minute would be a ridiculous cheat.
I would like an ending in which Walt briefly considers sacrificing his own life in order to safe Jesse's, but changes his mind at the last minute to save his own butt. And then Walt dies anyway, exactly because of this decision.
It would have something karmic, I guess.