[suggestion] Creating a Metropolis
So you have two or more nearby settlements next to your mighty capital and they start growing closer and closer to each other until they are suburbs of your primary city. With the new Civilization tech "Urban Sprawl" you're able to combine them into a special super settlement with a combined population and greater bonuses/efficiency.
This way you can deal with settlement spamming. My last game on a small map I ended up with about 30 settlements after conquering two opponents.
The Metropolis has just one city build/training option so there are less settlements to go through each turn. Time costs for buildings and new units would be lessened and the city would get the advantage of having all the tied resources of the suburbs linked to it. So if suburb 1 has a farm and suburb 2 has an Apiary the Metropolis would get both resources and increased trade along with greater bonuses. It should also get access to super awesome buildings and special bonuses.
A metropolis would have different levels of population and bonuses just like settlements do. A metropolis level 3 might have 10,000 people for example while a level 1 has 2500 or something.
So, rather than having 30 settlements like I did last game I might have 10 settlements and six metropolises instead making the turns go faster with less busy work and making the game have more variety and be more fun. I've always hated the idea of caps so rather than maxing out a city you can just keep growing and growing while receiving an advantage for doing so.
Here are some links to my other ideas relating to cities:
changing the way a city's base buildings work
https://forums.elementalgame.com/395358
Champions as city officials
https://forums.elementalgame.com/395552