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.
Ooh! Ooh! WILD BUNCH. We're going to get the ending from The Wild Bunch. Great movie.