Making the game more realistic

I made Stone Walls cost 15000 mnai and 15 turns to build. I also upped wooden palisade to 3000 mnai, and wooden walls to 4500.
I also made Rome have no walls.

Lastly, in order to simulate, late game, the massive cost of the Roman bureaucracy, I made Praetorian cohort and cavalry both cost around 5000 mnai for upkeep. I figured I'd just keep a couple in Italy, both for protection and for this simulation.

Thoughts?

Good idea. Walls are too cheap in EB considering the historical effort involved in constructing them.

For me, your prices seem a bit too high, though. I would make them:

Palisade: 1600 - 4 turns to build
Wooden Walls: 3200 - 6 turns to build
Stone Walls: 9600 - 8 turns to build
Epic Stone Walls: 25600 - 12 turns to build

This is a good idea. I do not like to see epic stone walls in nearly every city after 200bc. I may even push the price and time further, more like the trade port upgrades, making them more like luxury items for rich empires.