There are mods that increase the min distance between cities, however there is no ++ mod, with it also making the following changes:
For 5 tiles it would possibly look like:
1) Increase the district range from 6 to 10 (based on the idea that range = double min distance)
2) Increase the loyalty range from 9 to 15 (as above range = triple min distance)
3) Trade routes would see there range increased .. although I dunno if the above formulas would make it too powerful.
4) Toronto city state bonus would change to 5.
.. and there might be something else I'm forgetting.
For 5 tiles it would possibly look like:
1) Increase the district range from 6 to 10 (based on the idea that range = double min distance)
2) Increase the loyalty range from 9 to 15 (as above range = triple min distance)
3) Trade routes would see there range increased .. although I dunno if the above formulas would make it too powerful.
4) Toronto city state bonus would change to 5.
.. and there might be something else I'm forgetting.