The upcoming expansion The War Within will introduce us to the holy-fire-wielding Arathi of Hallowfall, who are descendants of the original human Arathi Empire. It is already speculated that due to their light-like powers that Anduin will have interactions with them to try and restore the connection to his own light; however, I am curious if another important leadership connection for Auduin could be looked into: him being heir to the Arathi Empire.
For context: the 2015 Warcraft film introduced (and named) Queen Taria Wrynn [wife of Llane, mother of Varian, grandmother of Anduin]; in the film (stated to be an alternate universe from the main game) she is the sister of Audiun Lothar - canonically the Last of the Arathi Bloodline, and our Auduin’s namesake.
Now, while Queen Taria was officially canonized into the main game lore (King Llan’s wife previously having been unnamed), her relation to Auduin Lothar, and by extension the Arathi Bloodline, has neither been denied nor confirmed (as far as I’m aware) at this point.
If they WERE to make that blood relation official in the main game universe, that would retcon both (the late) King Varian and Auduin into members and heirs of the Arathi bloodline & empire. While, yes, this may seem unimportant overall with the empire being long since gone- the very existence of this new group of Arathi we’re going to meet, that Auduin will no doubt meet with regards to his personal/character development with the Light, they could also allow him some personal/character development at becoming a King and Alliance leader again, which would have additional layers if the Arathi relation through Queen Taria was made official.