Granted, the Burning Legion would certainly still have Azeroth on its hit list- multiple failed invasions, including one that turned the Orcs from their subjects to one of their most vicious enemies, and also the Scourge split off from them as well here. They’d come back eventually for another attempt.
But it just feels meh.
I really was hoping they’d go somewhere truly new with the lore. Or at least a followup on something specifically from WoW. Like I was hoping when the title Warlords of Draenor was leaked, I was hoping to see a return to Outland- The Horde and Alliance would have recalled many troops to Azeroth to deal with the Lich King, the Cataclysm, and the war with Garrosh. Could have been interesting to see who tried to fill the power vacuum that would have created after the fall of Illidan and the withdrawal of Azerothian forces.
Such a followup on The Burning Crusade, seeing Outland(not AU Draenor) as it exists post-MoP , would be really interesting. Hopefully it gets some treatment in Legion- it would make a viable B-story to this expansion, even though I do think it warrants an expansion of its own. Outland would be a great staging ground for Legion and/or Azerothian forces, and each side trying to recruit powers that rose up in recent years to their side. Hopefully they at least throw a few quests our way, at a minimum the Horde and Alliance would do a quick check of Outland to see if there is any useful intelligence to be gathered. It would be nice to have the player involved in that, rather than just assume the leadership isn’t completely stupid and fails to realize the potential.
The proper Legion expansion, honestly, I was thinking that it would be ideal for the final expansion, when WoW is no longer financially sustainable, they kick off the final battle so they can go out on a high note rather than wither on the vine.