The Arche: there armies may not always be pike-based because of the sheer amount of regional units, but as said: they can train (and pay for) any army you desire. Not only are they facing very different enemies, but they also get to fight them on very different terrain (sandy deserts, stone deserts, steppe lowlands and high mountains, the very distinctive terrain in Asia Minor,...). How many factions experience this in the early game? And as most important feature: they can build truly expensive units, artillery and ships, which means you'll never run out of options to throw away your vast funds.