Introduction

Well, the main question, that have been worrying my mind from the release of game, is what the best strategy in city management.
Therefore, we have 2 questions to investigate. The local one- how to put districts in the city to get best income, the global one- what strategy os the best in city placements, should they take lot of territory or no, have we to merge them and etc. 

Here we start

In future, I will introduce some more experiments in city development and would be happy to hear your theories about it.
Now, I have made first small step for this thread.
I was investigating the local question. I know only 2 valuable ways of district placement relying on their adjacency bonuses: 

1) We can place makers quarters in small clusters and surround them by common quarters so they didn’t affect stability at all and we can spread them as much as we can

2) We can place makers quarters  in big clusters to get the biggest production income
Experiment on paper:

So, to investigate this question, I used formulas from encyclopaedia and performed following experiment. We look at small clusters of makers clusters (M) surrounded by common quarters (the star ⭐️). Count the cost of next maker quarter, count the only income from makers quarter and their adjacency bonus, then calculate how much turns it need to build next maker quarter and finally replace all common quarters with maker quarters.
The result:

It seems that including common quarters in your cluster scheme is not valuable. On the one hand, we do not lose stability at all, but on the other side, if they all were replaced by maker quarters, next maker quarter could be build 10 turns faster. To prove this theory im going to rebuild it in the game, but now it seems that it is best to place huge clusters of one type quarters and build common one only between clusters/on the border in case if you are dropping stability, or build garrison as it gives much more stability. The paper with calculation will be in comment section

About population:  I think it would be cool if after stack into 5 the citizens “upgrade” into advanced specialist and provide much more income, so the importance of distributing your citizens was important during all game and not only first era. (And then “upgrade” into 10 and etc, also maybe infrastructure will give them extra bonuses) 

About immersive part: had posted a thread about domestic policy dlc, where citizens shall belong to different nations and be coloured in colour of player nation and get bonuses depended on axes of that player. So the spread of culture into another land will affect new citizen that grown in it, so it will be dangerous not because of annoying osmosis, but because you don’t have citizens that apply your bonuses. In such term civics related to nations like monocuralism will provide stability bonus/penalty for your diversity. But I understand that it is so complicated in terms of programming, that we will never see such thing.

About units: will be cool if disbanded unit gave xp bonus to next built unit, so you can disband armies during peace time and recruit them during war

EsoulBoy wrote:
About immersive part: had posted a thread about domestic policy dlc, where citizens shall belong to different nations and be coloured in colour of player nation and get bonuses depended on axes of that player.

I like the idea, but so expressed sounds a little bit too complex to me

EsoulBoy wrote:
About units: will be cool if disbanded unit gave xp bonus to next built unit, so you can disband armies during peace time and recruit them during war

Actually this was more common in the ancient time, when standing armies were not a common thing, actually veterans usually suffered the return to the normal life. (Ancient) Rome introduced the role of the profession of the soldier and was the first to create a sort of a pension system for veterans (usually the state gave them a tile of land to farm [Reference]): what about creating a civic about it?