"Greece proper" is a modern conception which is of no relevance in 270BC.
If you were to map out a "Greece proper" in 270BC, it would include Sicily, the lower boot of Italy, Marseilles, half of the Spanish coast, the Anatolian Greek states, the northern and southern Black Sea coasts, all of modern Greece, Macedonia, and Albania, the Aegean Isles, Cyprus, Alexandria, dozens of other Greek cities in the Successor States.
And it has Greek cities for all of them, literally all of them.
And the only Greek state that isn't currently playable that might deserve to be so, due to its minor significance, is Syracuse. But not having it is no big loss.