Functional Conception of Factions

This is basically my outline for how I want each faction type to "feel" coherently in terms of its selection of units. We are aiming for historical accuracy above all else, but I think it's important to get the right "feel" in terms of how each faction plays out and to use this to try to achieve an overall balance that makes for a fun experience in multiplayer as well as an enjoyable single player mode.

Romans: Predictably, the Romans will have the best basic melee infantry and will probably beat anybody one-on-one in an infantry fight. To back these up, they have a wide diversity of auxiliary troops able to perform basically any function the army needs to. The Romans' big weakness is that their auxiliaries are rarely the best at anything.
General strategy: Make the enemy's terms yours and grind him down.

Sertoriani and Massylia: These factions both rely a lot on Roman-style infantry, but replace the flexibility of Rome's vast range of auxiliaries with local specialties in skirmishers and light to medium cavalry.
General strategy: Keep the battle on your terms.

Suessiones, Aeduoi, and Aruernoi: The Gauls bring large numbers of excellent melee infantry of all skill levels to the table and have good cavalry to play a supporting role. They're best at picking a fight quickly and have very good staying power to last through a long fight. Their big weakness is to enemies who don't fight on their terms, particularly at range.
General strategy: Fight fast and fight hard.

Pritanoi, Sweboz, and Lugiones The less technologically advanced European peoples bring superb militia troops and extremely skilled and loyal retainers to the battle. What they lack in staying power and armor, they make up for in fierceness, prowess, high morale, and devastating javelin attacks.
General strategy: Shock, then awe.

Dacia: The Dacians have a unique combination of superb shock infantry, very good skirmishers, strong archers, and good cavalry, and generally don't want to engage immediately without deploying all their ranged resources. Their main weakness is a lack of infantry with staying power - most of their troops will go down fast if the fight isn't going their way.
General strategy: Fl.

Hashmonayim, Ptolemaioi,Nabatu, and Pontos: These factions each have strong melee infantry, very good shock cavalry, and a variety of light local units to back them up. Their big weaknesses are at range: their missile units are great, but not amazing, and there's few great skirmisher troops available.
General strategy: Shock and awe.

Hayasdan and Pahlava: These factions have superb heavy and ranged cavalry, archers, and skirmishers. Their infantry selection is very limited and they shouldn't aim to hold a melee fight for very long: the battle should be over fast after the melee begins.
General strategy: Destroy the enemy from afar and close when the time is right.

Indo-Saka and Kushans: These factions combine access to the best bow technology and horses, superb metalwork, and the huge armies of India - able to crush the enemy up close or rain death from afar. They lack good skirmishers and individually flexible units, though, and their armies can fall apart quickly.
General strategy: Overwhelm the enemy at range, then up close.