I'd rather see it fixed economically. the 5 tile limit already makes it hard enough to expand existing cities. a 10 tile limit would result in fewer cities, but they still wouldn't have room to expand.

imo make any lvl 1 cities past your capital have a higher upkeep that lessons with each level. that would lead to fewer, more prosperous cities i think.

edit: sorry i forgot i was on the mods forum, not general discussion. this isn;t a mod I'd be interested in, but dont let me discourage you from trying!

I'd like it inverted instead. So you could only build cities close to each other. 

The city spam is what I really don't like in this kind of games. I even made some Civ4 "modmods" to reduce it and force the player to found cities gradually and leave some wilderness areas in the early stages of the game (Civ4 fixes this issue economically using the city upkeep costs, but it wasn't enough for me and I created some extra restrictions).

Not only the minimum distance should be increased, but also there should be some extra costs related to having a large number of cities (of course you should be able to have more cities on larger maps than on smaller ones). Maybe there should be a city upkeep cost that increases with every city you build or conquer (like in Civ4), or something different, like a limit to the number of cities that depends on technology, which gives a big penatly for having too many cities, which forces you to raze them or release minor factions.

It would make it impossible to colonize a remote island, for example.

Honestly I have to say it's probably better to have the tile limit at 5, if you set it any higher they'll just fan out their cities more, meaning even less room to build and more cities in places they really shouldn't be (that's always annoyed me about games like this, got an empire going with fairly well consolidated borders and BAM a pioneer decides to start a new city right in the middle of your area).

I'd really like to see a mod to buy and sell cities in the Diplomacy window. Best way to stop city spamming is probably make it costly somehow, like have an increasing cost in gold and materials to build each city.

i already asked the question, look at the last post:

https://forums.elementalgame.com/393977

edit: i modded things a bit and the AI seems to spam less but with broken improvements, i wouldn't advise it unless you want broken things too.

"""I'd really like to see a mod to buy and sell cities in the Diplomacy window. Best way to stop city spamming is probably make it costly somehow, like have an increasing cost in gold and materials to build each city."""

devs said AI doesn't handle this too well. I have a cost of 100 for each new city and it seems fine.

I think a method would be to implement a system where the more cities you build the higher a "risk of revolution" you have. 

What I mean by this is cities start leaving your empire/kingdom if this "risk" rating gets too high, just like your borders expand if you have high influence.  The break-aways would become new independents (or if captured could revert to original kingdom/empire)

I would prefer to see the upkeep costs increase the further hub cities are from your main city.  This would mimic increased economic costs to maintain far reaching cities as well as corruption.  Buildings could be modded in (courthouse, jailhouse, executioner, etc.) to reduce this upkeep.