I borrowed a page from Spitz and Frogboy's conversation in another topic and came up with what I think is a pretty good idea incorporating what Spitz has in mind plus something useful for Guilds to do that Also allows us to better Specialize our Cities. First, here's what Spitz said:

Quoting Spitz:

How about a soft limit on the number of available tiles for building? If you build beyond the soft limit, there's the risk of incurring a penalty. The available number would increase with each level of city.

For example, with completely fake/unbalanced numbers, for a level 1 city you get 10 green (no-risk-build) tiles, 5 yellow (moderate-risk-building) tiles and 2 red (high-risk building) tiles. At level 2 city you get 15 green, 7 yellow, 3 red.

For an example penalty, let's say bandits, or monster, or demons, (or worse, tax-collectors!) are more attracted to large cities. If you build in only the green tiles, you have no increased chance of your city being attacked. If you want to be able to build more than you have safe-building space for, you can, but for each yellow tile you use, you increase the chance of monster raid on your city by a percentage, which is cumulative the more yellow tiles you use. If you go out into using the red tiles, the chance of attack goes up by an even higher percentage.

This soft-cap gives the player interesting choices to make. Would I rather have a smaller city missing a few buildings, but less likely to attract unwanted attacks, or would I rather have every possible improvement, but have to spend more effort defending the city.

Other ideas would be increased maintenance costs, but the monster-attack thing is more exciting.

Frogboy liked that, honestly, I liked that too and also pulled in Frogboy mentioning wanting to do something with Guilds plus I have some of my own thoughts on a better way to "purpose cities". By that I mean having our cities specialize in doing specific tasks better then others. This is what I used to do with my planets in GalCiv 2. Certain planets would be near rich recourses and had high production capacity so I'd use them for building fleets. Some planets would have high populations which brought in lots of money and I'd draft my marines for landing invasions from there. Some planets just had high population and a research bonus on the planet so I'd make them all researchers. I think we should do the same thing in Elemental only spice it up Elemental Style....with Guilds. Speaking of Guilds, where are all those city level up bonuses coming from exactly? "Guilds" and "Guild Buildings" , of course  .

Spitz's Building Caps:

This plays an integral part of this. While I'm hesitant to give up a open building structure like we have now, I would welcome a change if it brought something useful to the table and allowed me to more specialize my cities. This way my cities seem more ordered in the scheme of my Empire. This would how-ever require us to once again be able to build multiple copies of the same building in the same city. It worked in GalCiv 2 and I think it can work here. Plus I have a further idea to make sure the cities don't end up looking stupid with mainly one type of building taking up space. In order for the rest of this to come together though, Spitz's Idea needs to be put in place first.

City Specialization with Guilds and Guild Buildings:

If I have a city that has a Fertile Land tile I'm going to want to specialize this city into my farming capital or "Produce Center" as that would fit Elemental better. If we only have so many tiles to work with I'm going to center my food growing buildings on or next to the Fertile Land Tile. After building so many food producing structures the player gets a message, "The Farmers Guild would like to operate in your City". If you say "Yes" then that city gets a Food Production Bonus and Access to "Farmers Guild Buildings". Advanced Warehouses or Grain Silo's to keep food stores fresh. Advanced Farms for breeding food-stock. A Farmers Collective to work together sharing planting knowledge, etc etc all kinds of buildings really, all Food or Farm Themed. This same thing can be applied with other types of Guilds and Guild Buildings as well, like a Warriors Guild which would be in the city I train most of my troops at, and a Miners Guild in the city where I mine all the iron I use to make armor and weapons. When a city levels up it gets a new bonus from its chosen Guild and access to the next level of "Guild Buildings".

The different Guild Types and City Types are only limited by our imaginations. Warrior Guilds (troop production), Wizards Guilds (magical and tech research), Farmers Guilds (food/produce production), Miner Guilds (resource production), Blacksmith Guilds (weapons manufacturing), all for cities that specialize in doing different things in their respective empires/kingdoms. One city is my center of commerce where I raise the most taxes so the Banking Guild comes to help collect taxes and make things more efficient. Another city specializes in feeding my growing empire, making sure caravans full off food get to their destinations. Yet another city is a haven for Wizards and Warlocks who unlock the mysteries of magic and research for my empire. Endless possibilities here, endless.

What Needs to be done for this to work:

First, Spitz's idea needs to be implemented. Second, we need to once again be able to build multiple copies of pretty much any building we want while having the bonus for those buildings stack or multiply when being built next to each other. This can be balanced by tweaking the bonuses themselves or through the use of balancing the benefits (or lack there of) of Guild Buildings. Some Guild Buildings may not be too popular and have a negative effect (Assassins Guild or a Guild of Death Magic).

Next, and I know this might seem like a big step back in the game's design history, but the importance of Caravans and what city does what needs to be re-evaluated. Like having all your Ore mined in one city, then shipped to another to be made into weapons and armor. Honestly, this can be done in a Fun Way (automatically), limit city spam while allowing for specialized cities (which you need with city building limits anyway), and makes defending your caravans and trade routes very important while adding logistical and strategic depth.

Later Expansion:

This opens the doors to do a Lot of things later down the road. With the introduction of Guilds and Guild Buildings you open up the door to the possibility of what else those buildings can do. Some of them could produce specialized units you can't get Any Other Way. Some Guilds and Guild Buildings can add unique bonuses while others may provide a very specific bonus while also hampering things in some way, example: Death Mages Guild. The Death Mages Guild offers advanced spells that use Death Magic, could summon powerful undead units, but costs a steady population drain on the city they are in which would also increase unrest in that city. Again, the possibilities down the road are Endless. Also when you factor in that every single resource in the game could offer it's own Guild that specializes in it's extraction and use that opens up a lot of doors because of the Huge Variety of resources in Elemental, from those on the map to your empires/kingdoms people them-selves.

Closing:

I really hope you take a serious look at this. With further refinement these improvements could do a Lot for both the game and for Gameplay. I know talking about specializing cities brings up the conversation we had a Long Time Ago when we were talking about the economic models, but the cons of the more complex system there Do Not have to be worked in here so I honestly don't think this has the same draw-backs that the more complex economic model had. In fact I think this avoids all of them while addressing the key issues we're facing now.

I also understood this is a lot to do or even bring up this late in the game, but, being ahead of schedule once again, plus looking at this from a Expansion point of view later down the road, I think at the end of the day it brings a lot to the table for the game. Frogboy, Boogie, give this one the "once over" and kick it around in the ol' noggin and see what you think.