It would actually work if they had built on that premise since the beginning and it wasn’t just something that they had invented for Shadowlands as an emergency back-up plan to avoid retiring a popular and iconic character.
It’s an interesting moral question, but the fact that it was pulled out of Blizzard’s butt for this expansion in order to wave away the consequences of almost twenty years of unadulterated evil makes it so much less interesting and just compounds the other issues with the character, the story and the game as a whole.
But then again, I’ve gone on this rant before in Pet Peeves.