There was not a point in azeroth history when orcs were "good" or even viewed as anything but savage and barbaric.
They don't have much (if any) redemption to do - garrosh is the typical orc, the orcs following him are also typical of the orcish horde... it is just orcs being orcs, no idea why do you think they need redemption OR to what should they be redeemed to, as saints???