How to balance Romans with other factions

I know there are mods but what are some good ways to balance the Romans on your own? This is with vanilla RTW 1.5

For instance I removed the ability to train Urban Cohorts and Praetorian Cavalry as those weren't supposed to be mass produced. Maybe reducing the armor slightly for their legionnaires? Less damage from their missile throws?

For those who have played with a lot of mods, what did those mods do to balance the Romans with the other factions? I like vanilla RTW more than the mods because there's less cities and it's simpler. But still I want it to be somewhat interesting without the Romans wiping out their immediate neighbors every time.

You can always try, the Vanilla Balance Mod, it balances the vanilla campaign so most factions have a chance of winning, and no one really mops up their neighbours.