Question/concern: It seems to me that there are two ways for a lord to control the income of his knights. He can either tweak their estate sizes or adjust their tax rate. Why is the latter still needed? If I want my knights to receive more/less gold, why can't I just increase/decrease their estate sizes? Why go through the extra step of making my knights pay taxes, when I, as lord, pretty much decides what share they get anyway? Is there actually an interesting trade-off between adjusting the estate sizes and changing the regional tax rates?
It seems to me that the regional level tax is just a needless complication, and another feature that needs to be maintained by the devs, and might break (or become buggy) later.