If it happens, Rome seems like the best best. Especially with later Rome as they used more "barbarians".
With the Roman history of barbarian warriors, slave labor, massive conquest, and citizen legionaries, perhaps Rome could be a civ where you don't build military units, you grow or by them.
Armies of Rome: Whenever you connect a city to your capital, gain a melee unit. All Great Generals can convert barbarian camps with gold.
Therefore as Rome, you don't make an army traditionally. You go wide to build legions and pay off barbs to protect your borders. Late game, left over barb camps are a source of instant units.
With the Roman history of barbarian warriors, slave labor, massive conquest, and citizen legionaries, perhaps Rome could be a civ where you don't build military units, you grow or by them.
Armies of Rome: Whenever you connect a city to your capital, gain a melee unit. All Great Generals can convert barbarian camps with gold.
Therefore as Rome, you don't make an army traditionally. You go wide to build legions and pay off barbs to protect your borders. Late game, left over barb camps are a source of instant units.