I have to disagree with this hierarchical approach.
Let's start with city-states. As the name suggests, they were exactly that: a full state, with a government, laws, army, economy, just limited to a single city and a her surrounding territory. Beyond some rural communities and very small towns, there was nothing in Attica but Athens (or in Beotia but Thebes etc.)
With "nothing" I mean "nothing different from administrative municipalities".
A city may have the hegemony upon other cities (see the Delian League for example) but this is more similar to have subsidiary or "forced-allied" states, and not the count-duke-king relationship.
Let's jump to the opposite range: large empire (Rome, or the Achaemenids) . Of course there were satraps or provincial governors, but again all the political decisions were handled at higher level than a single Province: their main duty was collect taxes and tributes, handling the public safety, eventually handle with local revolts.
Instead I would like to have a stronger focus upon the cultural and ethnic aspect of the population. Why Sparta (or any other greek city) didn't forged a true kingdom as, later, the Macedons did ? Because in Sparta there were just and handful (some thousands) of Spartiati.
Rome, on the opposite followed a policy of building colonies and "romanizing" the italic populations, and granting more and more political and civil rights.
But this take no less than three centuries (since the early sannitic wars up to the social war of 91 BC)
This kind of challenges I would like to have in a forecoming game.