I agree about the multiply-used plot problems & not being worth an extensive code rewrite. Also it would exacerbate my OCCPD (Obsessive Compulsive City Placement Disorder ) to the point where I can envision trying to frantically arrange city grids to have rims of specific tiles that need to be worked by multiple cities . But having a more gradual territory expansion like in C2C would be cool to eliminate the need for precise grid layout setups far in advance, and let cities grow more organically like in history while also letting generating YIELD_CULTURE to grow borders become more important. That sounds good. It does seem like in vanilla its too easy for any unit to found a city getting many buildings for free; I wonder if it could make sense to restrict founding new settlements to a few Professions that load up with the Yields needed to construct their specific citytype, while also providing some Yields in the new city to enable Building construction to get going there. (Is the AI able to found special citytypes effectively by adoping city-founding Professions, or is it dependent on the vanilla system where any unit can plop down a new settlement?) The many buildings that went into gradual construction of a Castle (or large Monastery or City) took generations of people living and working there to complete and expand, so it would be good to have a few base citytypes for feudal (Manor->Castle), religious (Monastery->Abbey) and burgher (Town->City) that start out with only a few basic tier Buildings, and you gradually add more to further develop it while importing yields necessary to continue long term construction. The profession that founds the city could also start it with yields like Food and Stone which would facilitate further continued development that you can customize as you like. I think the system NG developed for importing construction yields for Buildings under construction is an important advantage, so you can add some higher tier fortification Buildings that take awhile to complete and require Stone imports for completion, to simulate gradual construction and expansion of the castle over many years. That is possible and you can actually see something like that in action with the Progenitor Improvements in old 2071, where you can unlock Professions that can recover advanced yields from special facilities you find on the map (after you conquer the Killbots guarding them). As you note this doesn't use inputs and creates the Yields from thin air (also the tile itself needs to have some base Yield using a Bonus) so it's likely not good to use this to make some sort of rurally based factories unless it really is mining or uncovering them from thin air like 2071. But it could be good for special unique sites on the map, or buildable modern improvements that can generate Energy/Electricity (eg Watermill -> Hydroelectric Dam buildable on Rivers, Windmill -> Wind Farm buildable on Hills, Solar Farm buildable on Desert, etc). It would be nice if you could build some special Improvements like this only once per 1-tile radius, like certain Improvements work in Dune Wars and Master of Mana. You can also generate abstract yields like Hammers, Crosses, Bells from certain map tiles that are of industrial/religious/cultural significance.