It looks like Poland is going to get a whole bunch of nerfs in the next update. But there’s one change that I think could make the civilization more balanced and unique.
I would change the Liberum Veto church card. Instead of lowering the cost of Politicians in exchange for slower development, I’d lower the cost of revolutions instead. And I’d lower the buff from 50% to 30% less resources needed. That would nerf the card while also making it interesting and unique (let’s leave that fun to the Danes!). On top of that, this would fix a problem players face when they want to go for the Cossack revolt: they often realize they can actually reach Age 4 before they’ve got enough ressources for the revolt.