I saw many times when some resources(fish\attols\some sheep\etc) are 4 tiles away from your city, and there is not always a way to build a city there(no more space, or some terrain trouble). And it is terrible. So I think that there will be a good solution to add some building in industrial era or during some tech in that era to allow cities work one tile more. I know that there is a mod allowing that, but it's unbalanced I think(he modifies Hanging Gardens and imperialism branch as I remember) and I want to see such change without mods. And what do u think? Will such change add some troubles or some unbalance? What cons of such change can appear?