I wasn't quite happy with with the 1st and 2nd playthrough as Rome, because the struggle with Carthage faded too quickly, but after a few tweaks, the 3rd playtrhough (see image) is much more promising now. Rome-Carthage struggle is intense, and doesn't seem to be ending soon. The aggression changes are perfect for Carthage and its client states, now they declare war in a more intelligent way, all three factions are only at war with two different ones, rather than the entire known world.

Will update again, playthrough #3 is very close to historical situation. Rome has two armies, and they are draining the finances, (< 1000 gold per turn income). Exciting stuff.

NOTE:

I will look into adjusting Rome's aggressive level. Currently they are set at "VERY_HIGH" which makes them "warlike". This might seem desired to make them more aggressive, but I believe this might cause them to irrationally attack just about everyone they come across. The best choice might be to lower their aggression to HIGH. I will investigate...