Why not but as I hardly imagine a Cataclysm-like expansion. Maybe new dungeons or even raids would suit the purpose of displaying this new plot.
Interesting points yes. The miror of my Quel’Thalas-oriented revamp could imply Azuremyst Isles, why not as a new settlement for the Kaldorei - after all it’s ancient kaldorei land, quite near from Teldrassil, and Draeneï would have fixed their issues.
I do buy the Nerubian hint, as such a would-be Azeroth raid.