Well, isn't that conspicuous lack of action more on Garrosh's shoulders than Sylvanas's? If my boss warns me not to automatically charge people for things they don't want, yet I do it anyway (blatantly and repeatedly), and she
knows I'm doing it, yet does nothing to stop me because we're reaping the profit... where does the blame lie, when we both look like evil extortionists?
Surely it's not all on me. Empty lip service and general enablement take some of the cake, too.
Pre-Theramore at least, the Forsaken are the only ones who have made sweeping, unambiguous gains. Morality aside, the results are probably worth a little excess plague.
But yeah, I agree Blizzard have written themselves into a corner there. Sylvanas has too many sins for them to all die with Garrosh, and his downfall/Thrall's reinstatement seems to be how they're going to paint this incoming Horde-wide redemption story. It'll be interesting to see where Sylvie goes from here; and more importantly, how she fits in under Thrall's (you know, the guy whose greatest desire is to bow at Varian's feet and enjoy peace) rule again.