I've had to suspend some of my own disbelief regarding civilization decay. For the most part, the simulation runs best if civilizations are allowed to grow to their fullest extent. Cliodynamic pressure can collapse a state but not (by itself) remove them from the map.
I also implemented a few changes for armed forces. Recall the distributions of the ages for each race. Each hegemony is then given a standing army based on the number of civilians between the ages of 15 and 50 (relative to human lifespan). This number is further reduced by 50% (since mostly males will fight), 10% (not all will be fit to fight), and 50% again (not all are willing). This article was helpful. Each year, the army is appreciated by new recruits and depreciated by those who die in battle. I'd like to find a way to depreciate retirees as well but without a cellular automation I'm not sure how just yet.
This significantly speeds up the battle simulation as a new military calculation is not required for each battle. In addition, armies can depreciate to the point where they are no longer viable. The amount of troops able to be concentrated at a single point of attack or defense is as follows: \[H = {A \over c} L(d)\], where $A$ is the army size, $c$ is the number of violent conflicts the hegemony is embroiled in, and $L(d)$ is a function of the distance $d$ between the capital and the point of battle. $L(d)$ encodes the army's logistical ability to supply distant points. Large armies can reach further but require additional support. \[L(d) = {1 \over \left({1 + {1 \over s}}\right)^d}\], where $s$ is the support parameter $s=2.82$.
One thing that becomes immediately apparent in the early years is the small troop sizes. A hegemony of approximately 10,000 people may only be able to support an army of 1000 or fewer (and that's at maximum $H$). In the first few hundred years, battle numbers are commonly in the dozens of troops, not thousands.
I tweaked some of the secession mechanics as well. I'd really like to implement some promotion and linearization but I have to think about how best to implement it and whether or not it'd be too computationally expensive. Currently there are still some issues where polities will either fracture into a billion competing hegemonies or glom together into massive, continent-spanning empires.
It's interesting that most polities haven't been able to stick around long enough to reach higher technologies. Most of them end up staying around Tech 6 or 7, which is barely past animal husbandry; a party in these areas would be hard pressed to find any kind of good gear or even wealth. But I suppose glory is always there for the taking.
