My assumption is that when worldgen is completed this will be among our options, but until then, I’d love to see the ability to set a minimum and a maximum size for cities. Instead of one city size option, have two. The game would then, for each city it generates, randomly pick a value between the two.
Personally I’d love to have giant cities in my games, cities that are all but unapproachable. But it’s just impossible to run a game with city sizes set very high, because there’s virtually nowhere you can go that isn’t dense city crawling with zombies.
I think for future city generation options, I’d like to see the game distinguish between cities, towns, and villages. Cities would be larger and contain most of the possible structures, and have a larger number of megastructures like apartment blocks, hotels, hospitals, etc. Towns would be smaller, contain fewer megastructures and more smaller structures (more houses instead of apartment buildings). Villages would be the smallest and have fewer of the available buildings. Mostly houses, gas stations, some small stores. Farms might be attached to villages. And then have the possibility for towns to be directly adjacent to cities, and villages directly adjacent to towns, giving the potential for urban sprawl that has a dense core area and then thins out toward the edges until it’s just suburbs and farmland.
This would give each settlement a little personality. Sleepy villages in the woodlands would feel very different from a sprawling urban center.