I have played this game for 3000 hours, I find it very beautiful, but there are changes to be made: 

Diplomacy: I don't like having the top diplomatic agreements since the ancient era. the sharing of spies with the Romans? uhm, and the pact of steel in the modern era is not there? Why are there no coalition wars? Why can't I play with 20 civilizations? why don't civilizations develop from city states? I'm sorry to eliminate the other civilizations, because then I have few opponents. 

Civilization choice: I don't like being able to always choose between all civilizations, there should be some requirements to be able to take them, for example having a port to be able to choose Carthage, or a city with a territory on the sea to choose the Phoenicians. I would like more players to be able to choose to have the same civilization, maybe those who arrive later have fewer bonuses. I don't like it at all, that transcending a civilization only gives more points. should double his bonus (obviously carthage would be nerfed). 

City development: I'm not thrilled that cities become huge in the early ages. why can't neighborhoods be upgraded? build in height instead of width...

Thanks for your work guys

New World: I've realized that the AI isn't risky when exploring with ships. I usually launch my ships, even the most primitive ones, into the oceans, to see if they can find passage to another free continent. And I'm often the first to colonize all of the new world. It's a pity, because then I win supersimply.

Hundred Years War scenario: 

I always play on maximum difficulty, but it's too simple, England doesn't do anything, if it goes well, it makes some troops, but I destroy them immediately. I wish there were also other powers in play, spain, burgundy, savoy, brittany... having all the free space to expand is really too easy, especially with a france, which has all the influence points that wants. And why not be able to play for England?

religion: I often cite the religion of other civilizations, so as to get the bonuses without struggling, in the beginning it is better to focus on other things. Furthermore, adopting your neighbor's religion improves your relationships and the other cannot ask you for territories, but rather allows you to ask those who do not follow it. But that's too convenient. There should be a pope who asks you for dozens or forces you to make war on whoever he wants. In addition to the bonuses, religion should also have a sort of mental control over those who follow it... so at least it would be more realistic.

A1y0sh4 wrote:

Some suggestions are really cool and interesting, in particular I find really interesting the one about the cultures to be Indipendent People like, but I find most of them quite complicated to implement.

I personally do not see the difficulty of implementing the system. I imagine that the AI of city states is very similar to that of civilizations, but with some limitations, such as not establishing outposts, not engaging in active diplomacy. a kind of limited ai. well instead of going extinct a city state that reaches a certain share of value, turns into a civilization, with leaders and starts making outposts. in the same way a civilization reduced to a vassal will tend to turn into a city state and in the long run to disappear. the same civilization should not be able to create outposts, before having reached a minimum of cultural development, the same units should culturally get lost, if they go too far from home, a bit like an immigrant who after a few decades no longer feels like a citizen of where he was born but becomes a citizen of where he lives.