Continuing the concept of closed base on limited space:
Modular Building Concept
Instead to have a nearly infinite building list, in a limited space will be very nice to have the possibility to have modular building.
imagine having to unlock one or more technologies, and the ability to design a building that best suits the style of play.
instead of having the same type of building for different levels (steel, microchip, ecc...), just different tech.
The player will have available only few building slot list (10-20, a limited numbers), and each building will have few parameters settable by the player, like some old table game! you have "n" points available, and you can use for make only one resources, or 2-3 similar resources, or less resources but with houses slots inside, ecc ecc.
Maybe for noob player, will be nice to have a "suggestion" building setup.