How about this setup as an idea with factions in their groups along with their 'token' unit if applicable.

DELIAN FACTIONS
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Corinth
Athens
Thebes (Sacred Band)
The Delian factions are all similar in their foundation of a Hoplite core designed to win battles in the meat grinder with lighter auxilaries to protect their flanks. Their navies should be first rate. Essentially these factions are to replace the 3 Roman factions from the vanilla game. A senate faction would be some embodiment of the Delian League that was created for mutual defence after the defeats of the Persians.

GREEK FACTIONS
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Lakedaemon (Enomita)
Very small but very powerful army composed of Spartans with Helot auxilaries. VERY limitted cavalry if any.
Macedon (Macedonian Phalanx)
Weak, almost Barbarian style low level units, but an excellent upper tech tree as Macedon was a culture that became civilised over this period. Pike phalanx and Macedonian phalanx (superior to others). Excellent medium cavalry. Not much archery but should have excellent anti-building siege engines.
Latinium (Legion)
Again, a weak low level tech tree that peaks on the higher levels with the early Roman legionary troops (as in Pre-Marian Reform).
(Phoenecia)
If required should have superior navy and combine the Greek unit style with middle-eastern and African unit types - although not high level units of either.

EASTERN
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India (Indian War Elephant)
Exotic tribesmen units with war elephants.
Persia (Immortals)
Vast range of units reflecting the vast range of territories that this empire controlled although distinctly lacking in armoured troops or heavy infantry. Good light cavalry, elephants and archery.

OTHERS FOR CONSIDERATION
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Thracia
Illyria
Aetolia
Arabia