Each Age has a particular province soft cap, beyond which your state will enter the decadent phase and be at risk of desolation. This cap is cyclical, not linear. Very early on, empires may grow massive (Rome, Han, Persia), then must be small, growing slowly up until the late middle age, where another high point emerges. (Mongols, Francia, Byzantines, Ummayads) This again gives way to smaller states (Portugal, Spain), building to the industrial age, with again huge imperial potential (Britain, France, Russia) which maxes out again in the Great War age (Soviet Union, Fascist Germany, Imperial Japan) before snapping into a moderate and modern cap. (United States, China, Russia, India, EU).

This fixes a number of persistent balancing issues previously:
Rome will no longer collapse prematurely, but will very rapidly when the time comes.
The Rise of Islam event should work neatly, building a rapid empire, and then fragmenting.
The Frankish Carolingian Empire should fragment appropriately.
The Mongol Empire can exist, and should collapse appropriately timed.
Napoleon should be able to craft a united Europe before it ultimately fails.
Industrial empires will contend more with each other than internally. Thus, Great Wars are more likely, and will be bloodier.
The Russian Empire should be able to expand appropriately.
China should expand appropriately.
The Soviet Union should now collapse in the 1990s/2000s.



Age Cap #'s:
Classical: 500
Late Classical: 500
Age of Migrations: 100
Dark Age: 100
Feudal Age: 100
High Middle Ages: 100
Late Middle Ages: 150
Age of Discovery: 150
Age of Reformation: 150
Age of Absolutism: 150
Age of Revolutions: 250
Industrial Age: 500
Great War Age: 500
Information Age: 250