From Discord: Comprehensive Rework of Raiding, Buildings, and Prosperity

[Bismarckingit]

The mechanics of prosperity, raiding, and building construction are all vague representations of concepts from the Middle Ages, but remain woefully unconnected from one another. As discussed previously in Discord, there is potentially a way to represent these things more coherently and as an interconnected whole, without each mechanic being completely separate from one another:

1. Raiding should depopulate counties beyond merely ending prosperity periods, if consistently repeated. Stage one depopulation should be a 25% chance, stage 2 should be 10%, and stage 3 a 5% chance every time the county is raided at each stage of depopulation, to represent the refugees fleeing and devastation of crops that result from constant raids. This will make also raids feel more impactful than the occasional destruction of a building.
2. Upon being raided, a county holding should see its baronies each upgrade their walls automatically (though this can also be a percentage chance), potentially at the cost of the loss of economic buildings such as town halls, universities, or even hospitals. This can represent the act of civilians tearing down existing structures to reinforce the walls in an attempt to prevent future raids, and simultaneously the long term impact of routine raiding: The expansion of the "feudal society" and the weakening of the centralized state by empowering local nobility (namely, by making it harder for the player to siege down vassal counties that get raided a bit too often)
3. High prosperity, especially "booming" periods, should occasionally (about every 10-15 years, perhaps) automatically upgrade economic buildings and automatically downgrade fortifications. This is to represent how not all economic growth is top-down development, represent the natural decay of the usefulness of walls as a city expands, and render more peace-enjoying realms more difficult to defend if thrust into a sudden unexpected war. (The Theodosian walls, though, should probably be made completely exempt from this) Exemptions to automatic building should be constructions like levy buildings (with the potential exception of militias, which could be applied to rule 2) and universities, which are comprehensive public works.
4. In the same vein as above, if a booming county remains booming for an exceptionally long time (50+ years, or perhaps 10-15 if taken as an extension of castle town upgrades), castles in the county should automatically convert into cities, representing the growth of townships into new urban areas and the complete decay of the ability for castles to properly control and administer territory in the face of constant pop growth.
5. In the reverse, if a county suffers depopulation, buildings like castle towns should automatically downgrade as a result, as economic activity slows down, and cities should start turning into castle holdings if the situation persists. Exemptions to 5 and 6 should be capital holdings, for obvious reasons.
6. If a county suffers extreme depopulation for a prolonged time, the complete destruction of holdings should be a natural outcome.
7. In the same vein, if the depopulation is too extreme, perhaps even holding slots can be destroyed. Too much, and perhaps even the capital holding becomes a village...
8. Less severe diseases than the black death should also be capable of causing population loss.
9. The "Inspire levy" targeted decision for warrior orders should probably cause population loss, as well. I mean seriously that's just mass forced conscription-
10. "Targeted raids" could be a useful casus belli, and one that works to directly increase domestic prosperity and reduce it for opponents.

If all of these are implemented, this should be a way to not only more consistently see consistent growth in global development, but more accurately and dynamically represent the development of institutions, and more closely connect all of these mechanics that previously were separate, while soft-nerfing raiding due to not only the damage it causes in reducing economic value but also the inevitable response of the populations in the raided territories by fortifying their lands.