Adding to this, they should not be running around with robes and turbans.
Iron dome helmets and bronze scale armour for the big boys and some long robes and a shield on the chest (like the Assyrians) for the little guys.
Turbans should be depicted properly the current one in Total War is a shia-iranian style.
The tail of the turban should cover the neck and most Arabs in armies had it covering most of the face and neck.
Another thing please, BEARDS.
I have no idea why they don't have beards in Vanilla, beards were a sign of maturity and courage.
Also please please please make these factions playable.
You will be the first ancient mod I see to actually put any effort into the Arabs.