Fresh water should also be a major factor in growth because water is pretty much needed for anything to grow naturally. Settling near water has always been one of the major strategies in settling, and even to this day coastal regions or regions near rivers are more densely populated than dry inland regions.

A few thoughts here:

The most blindingly obvious solution to me is to require essence to found all cities, not just cities on barren land.  It's quite simple to understand, and would limit city spam quite effectively tghanks ot the hard limit from essence.  The cost on rejuvenated land might be less than barren land, and would need balancing, but would still be there.  As others have said, the other uses for essence also come into play here.

I really, realyl like the idea of having resource buildings buildable away from cities, and am somewhat surprised this wasn't the original plan.

The problem with "essence-costing each time, even on revived land" is that it doesn't make sense at all. If you have revived the land, and have enough people to found a new city, why couldn't you do it ?

Or another idea : why not an infinite tech "New city". You have a limited number of available cities. You want one more ? Research the tech. It would simulate the fact that new cities aren't built just because a leader want it, but beacause some people need to find new place to live. The civilization breakthrough woud mean you tried hard to push your citizens to expand through a new town.

Or you can have a city per 2 or 3 level in civilization. It's limited, but you can still get a new one if you want. No hard limit.

"Oh wise men, please tell us where to live next!"

'Yes, we will tell you, come back in a little bit."

"Wise men, have you found the answer yet?"

"Not quite yet, in a bit."

"Now?"

"NOT YET!"

*years later*

"Come my friends. We can found a new city... Right over there, near the other end of the giant lake."

"Oh wisest of men, you are indeed the grandest of all."

That could be the case with a nation that focus on magic :

"Oh wise men where should we go next ?"

"Dunno. I'm working on a new way to blast things."

"Oh. We'll be eating cookies while you think hard, wise-one"

Having pop controlled by one thing would be best. Having multiple factors is just too complex for too little benefit. If we want water to have a big impact, just set it so that areas near water grow a lot more food.

@ Outlaw, setting the import/export levels of food would be nice, although I don't think we are even having an economic system with that option. Its simply a hard Resource-Availability-Per-Turn from each networked source. This is why the Concurrent "Global Food/Pop Cap" idea is probably the most elegant and fits into the current system with the least amount of fuss.

We have been told by the dev team that the mechanics of the game can be changed fairly easily (as opposed to the Engine). Changing the way food operates (by taking it out of the economics/trading game and tying it directly into Prestige and Population) would, in my opinion, add ALOT to the game, especially in terms of having special, prized cities, and reducing city spam .... as well as having a more natural growth of only a few Prestigious centers of trade and many more outlying villages and hamlets.

Less homogenous, symettric, boring, and more interesting and Fun.

There was an interesting book called "The Warded Man" in which demons came out every night.  There were economies of scale in warding buildings and ground (i.e., wards have to be maintained and there are a limited number of people with the skills to do so), hence you tended to have large cities and small outposts by critical resources.  Same basic theory - there's some limited resource needed for towns and there are significant economies of scale in its use.

Far as I know, that is how food works. Other resources are supposed to work the way vieux described, but I haven't seen it with food. Settlements without their own food don't seem to get a percentage of food, I can grow them to city with no problem (so maybe its 100%).

Could be that food in general just isn't fully implemented in that beta or something, I dunno. I do know that per town setting import/export is a lot like the economic system they already said they aren't doing, so it's pretty unlikely.

I'd prefer food production and the various food resources weren't directly tied together.

If fertile ground is the only source of food, it's a highly unrealistic method, and takes away a lot of diversity in tactics when it comes to depriving production.  I'd much prefer various terrain types were contributors, and the fertile ground locations were simply high growth land.  You can grow food just about anywhere, you just can't grow it well.

I'd like farming and foraging in the nearby terrain to be something a portion of the peasants in the city do, automatically planting and harvesting fields in outlying valleys and other logical places, hunting in the forests, etcetera.  If it's an automatic process of the villagers, I don't have the fuck with it.  The existence of those things gives me added concerns to protect, and added targets to attack.

Perhaps even communities could be started around a settlement that worked the lands next to them to supply the populace, all automated so we don't kill ourselves over micromanagement.

I realize that it would be difficult to explain backstory wise, but the backstory can be easily adjusted with some sort of hand waving or other explanation, or it could just be considered one of those cases where gameplay trumps story.  The essence solution has quite a lot of gameplay advantages over the other solutions people have proposed, and that is enough to recommend that particular solution.

As for a story explanation, perhaps the corruption still seeps into the air, water, etc. and needs to be filtered.  Perhaps it's a tradition of suprerstition that cities have to have some sort of magical stone or ward to represent them.  I'm sure someone could come up with other story explanations for this mechanic if needed.

Should a city never flip back to the original empire (other than recapture)?

If there should be a chance, what would trigger said chance?

Water is ultimately the most important factor, in itself and also as it's necessary for farming.  However hard transporting food is, transporting sufficient water (other than canals/etc.) is harder.  Thus settling near water is more important than settling near food -- especially in a young empire where food distribution systems are lacking or poorly developed --  so water availability should be a more important factor in city siting.  I'd like to see water being necessary for city placement (magical sources are ok).

I disagree that having 2 factors (water and food) is too complex, but if it's decreed to be so, as food is a function of water (as Cerevox points out), I'd put water as pre-eminent.

I think the city flipping is not that bad an idea, given the fact that the peasants were loyal to whomever happened to be lord. It is not like the peasants get to decide what side they would join. If the law says that the uncle of the late governor becomes the new governor and the new governor answers to a different king, then that is who the town belongs to. It sounds natural and logical to me.

In real life there were countless conflicts over who owned what lands because several lords may claim the very same land. Now you can tell me that cities should not switch because that makes little sense and such, but in fact it dos make a whole lot of sense.

The problem with this is that it would encourage a very small number of super cities and not other settlements of any size. Simply because essence is so precious you would always want to get the most bang for your buck. A point of note is that the goal isn't just to eliminate city spam. The goal is to make an RPG-esque kingdom with few large cities and settlements of varying sizes as well as tiny outposts.