The struggle ppl are having right now is to make you understand that warcraft lore is not some immutable story set in stone.
They retcon things when that said retcon is “necessary” for the new plot they are creating.
Blizzard is a COMPANY not a writer with a point A to B to tell a story.
World of warcraft is VIDEO GAME, that needs to sell and make profit and that said profit comes from the world being alive and functional, and for the money to keep flowing, they would bring arthas back in heartbeat. Like they did with illidan.
So please stop thinking like blizzard is a person that honor their work, they are a company and money is the goal.