My preference would be:
Greek
Norse
Egyptian
Atlantian (renamed as Titans)
Celtic
Slavic
Chinese (but majorly redone)
Shinto
Aztec (or maybe North American mythology)
Some of the earlier posts seemed to have issues with Atlantis being included and it being too much in the realm of fantasy. I agree with that as it currently stands, but I think it is more of a semantic issue. The Altantian gods or ‘titans’ were drawn from Greek mythology and since Greek mythology is quite wide in scope, I don’t have an issue with them being included. However, I think they should change their name to ‘titan’ gods.
I suggested in another forum (My ideas for AoM2 - #8 by ModalChannel370) that maybe the choice of minor gods for each could be increased from 2 to 3 with each new god having new units and god powers. As an example, if we take Thor, we could have the following:
Classical Age: Freyja | Forsetti | + Idun (goddess of rejuvenation)
Heroic Age: Skadi | Bragi | + Freyr (god of fertility)
Mythic: Baldr | Tyr | + Sif (Thor’s wife)
I think this could be a way of making the existing civs more interesting while still maintaining their existing features. I would love to hear if anyone has any thoughts on that.