In the newest video, by GamerZakh, we see some very interesting things about "How do Cities Work in Civ 6?"
The video covers 10 main points about how cities are done in the upcoming game.
1. Unstacked - as previously shown...but does point out how it will possibly impact combat concerns.
2. Tile Usage - fewer tile improvements in game, but adds the Districts and Wonders outside the city, amount of tiles still balanced. Plus, empires are not as limited to smaller number of cities as in CiV.
3. Buildings - apparently 3 or 4 buildings per tile with some buildings (Granary, Monument, Ancient Walls, etc) still in the city center, but only a few. Now you build things like Temple in your Religous District; or Library and Academy in your Campus District and Barracks and Stable in the Military Encampment District. The City Center is a sort of district, but is not population size dependent.
4. District Types - 12 types (as far as currently known)
a - Campus : for science stuff
b - Commercial Hub : for Market, Bank and money stuff
c - Military Encampment : for barracks, stables, etc and once setup, your new MilUnits appear here. Walls get build here as well as city center at same time. Also acts sort of like the old forts from Civ3, in that can also fire on enemies (anyone remember Zone of Control??). This can be used stratigically for things like choke points, blocking terrain, providing for a Killing field, etc.
d - Entertainment : related to amenities for happiness. Circus seen in shots, but not as much info for now...
e - Holy Site : for religous things, like Temples.
f - Industrial Zone : Production things like Factories and that UB for Japan
g - Theater Square : Culture (and likely happiness).
h - Harbor : likely the most significant change in the game over the whole series...YOU DO NOT NEED TO BUILD A CITY ON A COAST TO BUILD SHIPS AND OTHER WATER RELATED THINGS!!! Wow! Naval units are built here as well as sea trade, food and such buildings and things.
i - Aqueduct, Airport and Spaceport are still to have any specifics as to them, but have seen some screenies with some.
That is only 11, but the City Center supposedly counts, but I am going to say that it is your +1 district (zeroth district...). CiVI Wikia does have a listing for Trade Quarter, so I am going to say that is the 12th one.
5. Colour Codes - At a glance for the seeing of the different things in cities by different coloration... making more ledgeable from other areas.
Blue : Science,
Red : Military,
White : Religion,
Purple : Culture,
Yellow : Commerce,
Green : Growth
Orange : Industry
This makes it much easier to recognize what a city is and does, so if you set up a trade route to a City that has a lot of blue for science, you get a bonus to your research from that trade route.... Or target for conquest....
NOTE: remains to be seen how decernable or not this will be for people whom have various forms of color blindness ...
6. Adjacency Bonuses - Bonus to districts next to things, like certain terrains (mountains), tile type (rainforest and possibly forrest), other Districts and Wonders. Bonuses are minor, but are accumuative when adjacent. This gives additional bonuses and makes placement to be very much map and terrain dependant (remember how you could only do a very few thiings with endless fields of grass or those huge forrest starts). You don't have to restart several times before you get a fair to good start, just change up how you play due to all of these new things...
7. Population - Limits number of districts per city population, One district per 3 pop.... which thus ties into your Housing....
So, size 6 allows for Two Districts in that city... no telling what happens to that size 6, 2 district city if it loses population for whatever reason (like starvation or other things).
8. Housing - Soft limits your pop growth limit.
But buildings also give you more housing room, so building a Barracks or Granary, for example, will give you more housing at the same time. New housing also allows faster growth to help fill that space. As the game gets into the later eras, you can build neighborhoods that will give you more housing for that city. Some terrain also effects your housing, like fresh water (rivers, lakes and Aqueducts) and other things.
9. Happiness - Goes back to like was in CIV, more local than empirewide, like in CiV. Luxes, Amenities and Civic Policies all have an effect on this. Terrain tile Appeal system that makes living in the nearby city appealing. Rivers, Cliffs, Forrest, coasts and other things. Natural Wonders are mentioned (guessing things like Great Barrier Reef, White Cliffs of Dover, Fjords, Everglades, ...). So chopping it all down, filling it all in and mining or farming it all is not as appealing as having a great Swamp or forrest or whatever else that makes a city built on whatever grouping of terrain to be someplace that your people will want to live there... And don't forget the appeal of your Great and National Wonders....
10. Modernization - Things now can change over time. Can replace farms and other things as you go through the game (without taking a hit). Your farming (and other) techs, over time, will allow for a greater yield per tile. So you can give up a bunch of farm tiles to newer districts or revieled resources like coal and oil. From Farms to Suburbs...
[CONJECTURE] Plus, older resources, like Stone Quarries for one, can be repurposed as you have need for something else in that tile... And that old resource no longer has any real use.
So, your game will be different everytime, removing a LOT of the limited paths to victory gameplay that has been the bane of previous versions.....
Additional things that change over time are things like:
-Diplomacy going from very Wild West to very Formal
-Gossip through trade routes evolving into more advanced Esionage/Spy system