Golbez was being mind controlled wasn't he? That's less a case of redeeming an antagonist so much as freeing a pawn being controlled by the actual villain.

She's not pureblooded garlean, but Fordoloa seems to be heading in that direction if she isn't killed off in the near future. We also have Gaius' redemption, though we didn't really play a part in said redemption, it all happened off screen between us beating him and his reappearance.