If Anduin's Legion cinematic is any indication, the Naaru NEED him in the distant future as their champion. I could totally see A'dal or some previously unseen avatar of the Light appearing in a patch next year and ordering the Jailer to release Anduin or face the entire Army of the Light.And let's be real, here. Turalyon and possibly Velen would absolutely bring what forces of the Alliance are loyal to them along for the ride. It could be the means for shoehorning the faction conflict into the xpac.
I’m interested to see if we will see Saurfang at all. We know he’s in the Maw so it might be nice to see him get to the afterlife he deserves after we fix the death machine.