How great a unit roster is doesn't matter much. You will always have good enough infantry available. I am playing a migrated realm. Koinon Hellenon --->Massalia. My main front line consists of celto-hellenic spearmen. I have pretty much defeated the Iberians,Carthigians, and Roman elite armies with average troop composition. You are facing an AI not a real player, so even with lesser troops, you still have an advantage.