During mid to late game EL ES and even Civ sessions I noticed that empires tend to loose any unique structure they had before that might be the cause of game fatique for some (I usually quit the game myself at that point)

In the early to mid game this is not the case as early limitations on resoruces and time cause each region and city to be at least somewhat specialised (harbor; coin generation, military training, border region...). Over time 4X games tend to run into the logical issue though that all cities start to have all the roles at once. This is logical as earlier improvements become relatively cheap over time and as player economy grows they can be quickly aquired via buyout. The process of gradual econmic progression is needed of course to have a sense of progress else the player would be fed up if the growing empire would be crumbling under its own weight by artificial limitations all the time (food, moral, sanitation ec)

EL had an additional issue of cities growing over time which meant that they gradually took over a region and effecitvely negated geogragphical diversity as most of the map became a mass of huge cities laid out in the pattern of regions. This also made the world feel small as even though armies still needed >10 turns to travel around the map on larger maps, a considerable portion of that map was made out of huge cities (not a single small city around)

As far as I can tell this will be mitigated by HK by not limiting districts to be built around city centers allowing them to be spread out a region and lets say: follow the topography of that region instead of a typical hexagonal spread of the city center

On top of that there seems to be tierd infrastructure update here which I hope mitigates the spamming of low tier improvements in every city

Still, cities grow and some streams show exactly my experience where the test player spams buyout dozens of times a turn - this both drags out turns, is repetitive and take away the structure of the empires by making each city identical

I hope this will be improved in some way: by introducing upkeep cost to infra improvements, limit their number based on pop or some other method

In general I belive that incentivising players to place districts outside of heir main cities might be the key (by icnreased overal economic output at the cost of vulnerability and missing adjacency bonuses) as such districts will not only not be fattening all cities making them all overbloated and look alike but also add much needed diversity to the regions and the overall landscape.

e.g.: Instead of having empires contain only 4-8 megacities, players can now have outposts, forts, hunders of small towns, some mid sized cities and maybe 1-2 mega cities

This seems like a winning formula that should give empires a personality and is also quite realistic as it lend a feeling of the scale of a true empire with structure (newly occupied or centsted bored regions with low population density, worked (safer) inner regions and 1-2 city centers housing empire adminstration)

Havent played the beta and this is only based on EL, ES, CIV gameplay and HK videos but hope that there is a guiding principle in the design to break up those homogenic megacities from EL - based on the videos it seems to be going in the right direction for that