Cabinet rework
It makes no sense that a 1 location county with a tax base of 0.5 has the same number of (base) cabinet seats as a 10 province kingdom with a tax base of 50.
Instead I think that the number of cabinet seats a country has should scale with its economic base and to a lesser extent its size in the form of a bureaucracy-like slider and some sort of modifier according number of provinces. Richer states can afford to invest more in their government and so that should be reflected in game.
As well as this, the slider mechanic would also give the player flexibility - if they just conquered a lot of land they might want more cabinet seats for integration or if they are in a lot of debt they might want to cut down on cabinet spending etc.