I recommend picking up the eras pack...........Rome is a great game and if you don't want to micromanage evey little thing there is an option to turn on "manage all settlements" in the game. This will handle building, recruitment, and taxes, although it is not quite as effective as managing the settlements yourselves.

Plus, if all you want to do is lead hordes of glorious warriors, there is custom battle and i think 8 historical battles for you to do. And in BI you can play Horde factions like the Huns which don't have to settle into a city if you don't want them to.