We have Outland, which is a broken world on the brink of destruction. and then we have Draenor which shows what the intact planet would look like. But since Draenor is from an alternate universe then lorewise it cannot be explored too much from a lore perspective. AU Draenor was supposed to give us a glympse of what Outland used to look before it got ripped apart.
And now the residents of Outland live on a dying, shattered world, even though it is a place that many call home. Thrall for instance actually left to settle in Nagrand before Saurfang found him during BfA. And there is great potential within Draenor should it ever become whole again.
The mortals have already shown the titans their worth, and seeing how the titans are all about creating order and healing worlds, and considering that one of the biggest threat to the mortal world (the burning legion) is now defeated, Is there a possibility of titans lending the mortals a hand in repairing Outland? which is one of the shattered worlds in the WoW universe. Such expansion can see us mending the planet and moving to different zones that the titans are reshaping/repairing, and aiding them with taming the zone.
Perhaps races such as ethereals and Arakkoa can be brought back to assist the players in reshaping this newly forged Draenor. With the Titans only concerned about reshaping the world and not meddle in mortal affairs, we can be tasked with overseeing the little errands such as helping these broken civilizations find their path on this new world.
But how else can this expansion work? from your perspective. What does it take for Outland to be repaired, and what would you like to see in that expansion?