Who cares about some grumpy old lich? Why would he be worth considering if he got or did not get redemption at all? He killed some people at various points in his regal careers. So did everyone else. So did we. We’ve probably as players destroyed 1 billion times more life than Arthas ever dreamed of. He’s a nothing burger.
And I don’t get being all fixated on Teldrassil and Sylvanas either. OK, she made a call to raze a city. Oh, so horrible, right? I can go sit in Stormwind on my Rogue and kill the same number of innocent people in 15 minutes any time I want, no consequences. None of this adds up at all.