I'm around year 230 bc atm with around 50 provinces. Got 6 elite armies with +3 armour, +3 attack and atleast +3 exp units (Usual setup is 12 imperial legions(up to 2 first legions), 4 archers, 3 cavalary and general). Later versions also have up to 2 onagers after my 2 heavy onagers took down 400 enemy soldiers(25%) in one single fight. (mind that I'm playing with medium sized groups(42 men in legion etc). I also have tons of troops that I haven't really counted. They have just been trained where they are needed bringing the total upkeep of my armies to 90-100k per round.
Fighting against Ptolemaios near Nile with 2, Iberians(they have 2 provinces left) with 1, Gauls(3 provinces),Germanians(they still have quite a few towns) and Brits(no provinces on main land anymore) with 3 elite armies. Still the only real problem seems to be civil uprisings which slow me down but they end after a few exterminations. Also I still don't know how to fight elephants so I let AI do all fights against Ptolemaios (actually many other fights too since the game seems to get really slow after some fights).
Anyway it seems there is no point in making any important long plans since before I finish germanians and brits some new enemy has probably attacked me already