First, I think everyone should read this post.
https://us.forums.blizzard.com/en/wow/t/why-a-forsaken-player-is-frustrated/393567
It’s a fantastic good-faith criticism of the problems with BfA and Before The Storm regarding the Forsaken, and their part about Nathanos is spot on why I don’t like him - he was a waste of the narrative.
Nathanos being a jerk is fine. His actual character itself is fine.
Having to blindly follow quests because he said so dragged on way too long, but that’s not necessarily a fault of his character itself.
But Nathanos was one of the most prominent characters of the Horde story and he built up to nothing.
There was no payoff.
Worse, he leaves a hole in the story, and the only potential characters to fill that hole are pretty bad choices.
Nathanos is not without traits that can make him a good character. He even has quirks that are funny.
For a long time, I held out hope that Nathanos would amount to something in the narrative, but he didn’t. So if he’s not going to amount to anything or mean anything, he should stop being a part of the story and should just be removed from the narrative.