I want to effect methodology, because over the course of the first few turns it's becoming apparent that there are no limits to the players' capabilities. I want there to be some sort of give and take between the players' determining the shape of the world, and the world determining the shape of the players' factions, instead of the former dominating the latter.
Begin with a list of how the world will affect players' stats. What are the forces at work and the rate that they can change things. Include both the forces for growth and erosion, order and chaos, etc.
Then list the player tools that can be used to offset or enhance those natural forces.
If you set the rate of change that happens without player intervention, you can then tailor player actions to offset those at some appropriate rate. Does that make sense?