I would not underestimate roman importance.
as early as the 5th century several contracts between rome and carthage, or rome and other powers and city-states indicate that roman influence and power was "internationally" recognised at a very early stage.
I am actually pretty surprised that it does not come up as an independent fraction in this mod... around 509...
as for a hypothetical hegemonia 2, set after the persian wars, not giving the city of rome (and other italian tribes, peoples, and city states) a fraction-status would be historically inaccurate...