I fully expect Northeron to be part of Midnight. That little zone north of Stratholme that shows on the map but has nothing there. (The name was later reused in Twilight Highlands, but they are two separate areas.)
https://www.reddit.com/r/wow/comment...eron_from_the/
I think that whole messed up area up there, from Quel'thalas, to Northeron, to the weird smoke wall of Stratholme, being on the TBC servers, and the loading screens, will be repaired and updated for flying. This area has needed more work since Cataclysm, and I think Midnight will just be an excuse to fix all of that stuff. Since the devs have made it clear that they will only go back and update old stuff when there is a narrative reason to do so.