To be totally honest I hate the direction that cities in elemental are moving. The idea of placing building individually and having every building be a discrete location in the city. Yeah it seemed like a nice though. But in the end it seems nothing more than no value added micromanagement and meta-gaming (spider-web cities). Furthermore the differences it creates in cities seems more cosmetic than anything. So the big question. What really does make a city unique and memorable? Simply put it would be the character of it's people/location/development that differentiate it from other cities. In the civ games what differentiated your cities was the terrain that surrounded them and the special resources they had available and very rarely it's strategic location. That determined what type of city it would be. But really that was rarely enough to truly differentiate one city from another to the point that it was really memorable. The people had no character. And although you could build wonders often the decision of where to put a wonder was more decided by the city with the production to actually build it than anything else.
So somewhere in that giant thread about making unique cities I saw someone with a suggestion that I think has some serious merit:
Treat cities as RPG-characterlike entities.
It sounds a little crazy on the surface I suppose but it's not so far fetched. We already do this a little with factions. We give a faction a culture and then with that culture comes pre-defined bonuses and penalties. And sometimes in games you find things that give empire-wide bonuses. Kinda like little level-ups. So why not do the same sort of thing with cities only have the culture, history, and traits of a city emerge dynamically based on what happens to it. Make building up, developing, and nurturing your cities more important than just plopping as many down as possible to lay claim to as much land as you can.
So here's my idea in detail. Give your cities a kind of giant info card or stat sheet (like a character). It might look something like this:
Here would be things like population, wealth level, education level, health, etc.
This would be the interesting part. Here would be characteristics that the city had developed that defined it's character. These could appear from historical event, surrounding terrain, randomly, or by your own actions. Characteristics could be changed but not easily or simply. Here are some possible examples.
This town has been a center for military development for quite some time and the people here feel they have a proud heritage. The youth aspire to one day become soldiers and the most respected men are vetrans of wars past.
Cause: Over time a large percentage of the of population of the city has been recruited into the military.
Effects: Military units created in this city are stronger than average. Higher chance of hero generation. Lowered production due to the fittest being drafted.
The people of the city have little interest in learning new things. They know what they know and they have stuck to these things for many years and have no desire to make any real changes.
Cause: Ignore a cities development for long enough and allow it to sustain a low education level for some time.
Effect: Raising the education level of the city becomes more difficult and the people are less willing to benifit from new ideas reducing the amount they benifit from advances.
Longstanding enmity with (insert empire name here):
The people of this city have a deep and abiding hatred of one of your neighboring empires. The people will obstruct any sort of peaceful coexistance or amiable relations with them but will be eager to help in their downfall.
Cause: Has been attacked/raided/looted many times by the other empire
Effect: This city will not allow foreign trade with the empire in question. If you make peace with their bitter enemies expect their happiness to plummet and possible unrest. On the other hand if you go to war with their enemy the cities happiness will increase greatly and their military unit production will be boosted.
Resentful of your rule:
These people don't like you. They don't want you ruling over you. They might even prefer you weren't alive. Be careful.
Cause: Treating the people badly for too long. Especially in a captured city. Capturing a city that had a longstanding enmity with you.
Effect: Bad things. High unrest, poor production, potential for revolt, etc.
The people of this settlement have been hardened from long years in an inhospitable environment. From facing danger on a daily basis they are canny and tough.
Cause: A settlement in hellish like conditions (like swampland or dangerous mountains or something)
Effect: The people are tough and the cities health will not drop as easily as others. In addition soldiers recruited here will be stronger. However the people are more interested in survival than learning or the aquisition of wealth.
The people of this city are very friendly and welcoming. They enjoy making friends of all sorts.
Cause: Maybe faction based with a random chance or encouraged by the actions of your sovereign...
Effect: Boosted trade and a diplomacy bonus for empires with cities close to this one. Easier to infiltrate if spying is in the game and technology and the like can be stolen easier.
The people of this city are fiercely devoted to their sovereign and will follow him to the ends or the earth and to their death if need be.
Cause: Your sovereign spends time in this city preaching to the people.
Effect: Happiness boost every time the sovereign visits. Cheaper to recruit soldiers and they have a significant bonus to strength when with the sovereign. However if the sovereign doesn't visit for some time happiness will go down and eventually this will be lost.
The people of this city are free and forward thinking. Always looking toward the next new discovery or advance they seek out knowledge and adventure.
Cause: Can randomly develop in a city with good education, wealth, and health
Effect: Boosts idea creation in the city greatly and it is cheaper and faster to implement new ideas. Education levels are easier to raise. Slightly more expensive to raise troops and may cause slight unhappiness but city is more likely to spawn heroes.
There are many many more... I could think of dozens just off the top of my head and hundreds are definitely possible. Also you could have rare and unique ones brought on by artifacts or special events.