None of your "exploits" are actually "exploits". They are consequences of the change. Exploits are ways in which players could game the system to achieve unfair advantage, or do things they shouldn't be able to do. For example, an exploit could be a lord swapping his region back and forth between 0.5 and 1.0 every other day, thereby feeding his region for 0.75 normal food, while suffering few or no consequences if the penalties for running short are not big enough.