Imperium Universalis simulates this with a food system. In antiquity, people had to worry about this thing called food. Though still in development, the mod already boasts hundreds of playable nations from antiquity, mechanics like Senate debates and historical events like that time Kirk Douglas kicked off a slave rebellion. Ruling over provinces also costs Governance Capacity, generated by the primary culture, but reforms can allow you to give more authority to other cultures, embracing diversity.
All mods are compatible with the most recent version of the game 1.
Tweaks, fantastical overhauls, graphics improvements - modders have given the game plenty of love.
