Thank you for having an opened minded response to what I was saying. Some people don't want this to be a thing, either because it takes away from Arthas or it gives Sylvanas(the good one that arthas killed) a pass and puts the blame on the evil one we see before us.
I've been playing a lot of Cyberpunk lately, if you've played it than you understand where im going here with this. The main character *Spoilers* dies at the end of the second act, but you're still alive and play the game. It's because the technology in you, copied you and re uploaded your conscious. But it also uploaded the conscious of someone who's been dead for a long time. Eventually Johnny's conscious will overtake yours, not instantly, but slowly. You'll start acting like him, doing things he would do until eventually you become him without knowing it.
Another point in the game, they explore something similar to this with people who are alive, but are having their personalities changed by a shadow group(Mr.BlueEyes). They can be made to forget things, or remember false things. They can be encouraged to make decisions they wouldn't have before.
These 2 elements are really fascinating, they make the lore of the game very thought provocative. And I oddly enough I started playing the game after i made that post about Arthas and Sylvanas, yet it is what I've been saying is going on with Arthas.
Arthas basically died between the time of him picking up Frostmourne and when he ran off after killing Malganis. His personality is changed, rewritten by this evil dark lord. Any actions taken afterwards, aren't that of the Arthas that tried to save his people. Sylvanas aswell, despite not being loyal to the scourge, is overwritten by the scourge, but tortured right off the bat, so she hates the scourge. She's not the same sylvanas.
At a point in CyberPunk, you have a talk with Johnny about how he's not the real johnny(something he is aware of very early on) but it's about how the real Johnny, if there's a heaven/hell, is already there. No matter what you or johnny do, the real ones are already dead.
but people don't want that, because it takes away from Badass Arthas and evil Sylvanas who needs punishing. :/
Speaking of Shards! Jack maybe this helps a little with coping with the scapegoat that exists in other medias