I think I get where Sinelius is coming from and they can correct me if I’m wrong…
This is another example of Blizzard taking a villain that should have been their own xpac because of how powerful and lore-important they are and just making them a patch. Azshara is a great example of this too.
I admit I might have missed something but Xalatath is someone I just started hearing about in Legion but the void lords is something I’ve been reading about since… vanilla, I think? Remember when Blizzard used to have a page dedicated to their lore on their official website? I would read it on patch days. Anyways, I don’t think they should have been one boss in one patch.