But again that would imply that there would have to be a Food repository for that purpose whether it would be an Empire or city one.
Obviously the city food production would be the current one tying any unit built to that one. This would again cause cities to stagnate or shrink if you had to field any units for an army or for defense of that city. Unless Food production was upped significantly. Which would reverse the current mindset of the Modding teams goal over Food production and limiting city growth.
Currently you would use all your food production up on units like the Town Watchman to combat Crime, or the Healer to Combat Disease, etc. You would not have much if any army.
Again make a mod mod out of this and see if it works.
JosEPh