OK Leoreth you win. By refusing to remove Poland you leave me no choice.
Here are some suggestions on how to buff Poland.
- Improved UP: Golden Liberty
Foreign Culture causes no Unhappiness or Instability, and is dominated by your Culture in your cities BFCs (meaning, you always control your cities' BFCs regardless of Foreign Culture).
^ The second half of this UP (new addition) is the Chola UP of RFCA as well as the Serbian UP of RFCE++. In both of those mods, the UP makes a small, late spawning civ in a crowded location viable by giving them necessary room. Poland in DoC faces the exact same problem.
- Hidden Boosts to Religions
More religions should spread automatically to Poland. Let more Missionaries (Catholic and Orthodox) spawn in Poland some time after its spawn like how Orthodox Missionaries spawn for Russia and Buddhist Missionaries spawn for China.
Make Polish AI prioritize religious buildings, esp. Monasteries since it's the best way for Poland to get decent Culture and Tech rate.
- UB: Extra Happiness
The Polish UB, given what it represents (pre-Modern democracy), befits an extra (+2 would be appropriate and comparable to Theocracy) Happiness bonus. An earlier form of the American UP, if you will, but with the purpose of making City States more viable as opposed to Republic.
- UU: Hidden Tech Discount
AI Poland needs to be made to prioritize Music => Military Tradition. Perhaps a hidden discount in the research cost for Military Tradition is in order.
- Map: Independent Memel/Danzig/Riga to flip to Poland
The best way to avoid AI settling of crappy city sites is to settle cities for them.
^ There. I think all or most of these combined will make Poland less pathetic and more relevant.