The next expac would be the perfect time to revamp the old world again since we will finally have a functioning earth warder. Either Wrathion or Sabellion could help repair the damage done by Deathwing, thereby giving a lore excuse to bring kalimdor and the EKs into modern WoW.
The other aspects could help as well, with Kalegos fixing a lot of the magic shenanigans going on and Merithra helping restore nature and stuff. This could allow places like Desolace and Felwood to finally be restored. Same with the plague lands and Silithis as the scourge is basically no more and the old gods corruption is supposedly no longer spreading (giant sword is still an issue tho).
It could even be possible that the sundering could be reversed as the titans are alive once again as well. Khaz’Goroth, along with whoever the earthwarder is, could pull the continents back together. This could get northrend included with the revamp, AND allow them to create one huge continent that would be perfect for dragonriding, as the current EK and Kalimdor are pretty flat for the most part (excluding the borders). This could also be justified by lore as all the inhabitance are now holding each others hands and singing kumbaya (in lore the mountian borders were created by neltharion to prevent the mortals from picking on each other).