Try with Jamestout like graphics :On the other side, I planned to have cities need flat room to build some structures, having them placed on map, making these tile spawn point for designated units build by the city (eg, a "Samourai Archer" built in the city would spawn at the archery's tile), and making cities spread out a little (within its borders, from center to outskirts)
This should give something like that :
[IMG alt="Exemple2.png"]https://forums.civfanatics.com/attachments/exemple2-png.621777/[/IMG]