i just gave the romans 2 full legions, one in the north and one in the south... i install 2 generals who lead them as consuls... now this may look like it is easy and at the start it kinda is... but there are rules... i only use those 2 armies, no other but quick raised levies to fight of rebels. so when you expanded your empire to some extend those 2 legions really dont do it anymore and the fun begins. had some really fun battles using the quincunx formation.