I was wondering,
Civilization always missed something in war times. Dirty street war in big city's that cannot be taken in a few turns. You know like Stalingrad in WOII: The germans controlled big parts of the city but it never actually fell into their hands.
So I was thinking why can't city's expand on one more tile after they grow to lets say 15. You have to spread you garrison units but a city never falls in one turn if you forgot to pay attention to your borders for a few turns. Also a lot of buildings survive if only half of the city was captured. And maybe for example if you build a cottage next to your city in the beginning it grows to a town in the future. That town can later become part of your city if it reached a pop of 15. The town will still hold its value. But new buildings constructed in the city will end up in the town that joined the city.
Is this a good idea?