the Skaven being disliked by Archaon makes for an interesting concept. If the Skaven were to gain as much traction as they seem to be (mind you, the AoS timeline can advance), where would Chaos end up? obviously the Sigmarites, the Seraphon, and whoever else would fight the Skaven, but if they were a bigger threat, would Archaon unite with them? As we know, Archaon isn't an unreasonable person. The leader of the Warriors of Chaos, sure, but lawful as well.
Definitely something to consider buying next.