I would like a timejump of a reasonable period (decades at least) and a return to Azeroth but Ironforge is under siege (from whoever the new "big bad" is), Stormwind is completely destroyed and have something similar happen on the horde side too. Expansion based on working out what the fuck happened and rebuilding major cities and retaking zones (rebuilding cities could be similar to how Isle of Quel'thanas worked in TBC with it being built up over the course of an expansion with players helping in some way).