I had an idea that you could "trade" your excessive goods to other nations in return for ducats or other trade goods whos modifiers you would like . Like say Mamluks have excessive grain and they dont need the some of the strategic bonus( what is it? land force limit?) modifier they can trade it to Venice for money who needs the strategic modifier for whatever reason . and the strategic bonuses scale with the amount of provinces you own or trade of them. So say you have 10 grain provinces giving you x FL but only need x/2 FL you can trade the excess resource to other nations. I thought it was a decent concept and closely resembles one of the reasons nations trade in the first place. I'm sure theirs a million reasons why it wouldnt work though