Could The Fimir Ever Return In AOS
I have always enjoyed these guys ever since I first laid eyes on them in Total War. Sadly, their old lore is a little problematic, but I blame the time period in which they were created. I think they could come back better than before.
GW could rewrite them as a faction that knew the World-That-Was was going to end. They threw in with Chaos, saw the bigger picture, and knew they had to get out of dodge. They either created or discovered a new realm and slowly left. This would explain why there were fewer and fewer of them during the End Times. From there, they could create a new civilization or faction.
They would still worship Chaos, but view Archaon and other Chaos groups as usurpers. I’d want them to return to the Mortal Realms as an anti-Chaos Chaos faction.
It would be cool to have a middle-ground Chaos faction that is likely to throw in with the forces of Order as they would view the current Chaos factions as corrupted usurpers.