Something I've considered is making a Civ Like game, but with far more flexible units and cities.
The main unit in the game becomes a "Group of People". GoPs are the members of your civilization. They are your armies, your workers, your settlers, and your cities. As long as they are in a tile that can provide abundant food and shelter each GoP will slowly increase in size (and power) till it splits in two, except all GoPs on the same tile will feed into the same new unit.
While on a tile they can create improvements or take actions with what is there. They can 'gather food', or 'construct improvements'. Each GoP will have a limited number of turns they can last without food, which can be increased with technology and improvements. Units could 'share' food over a given range, which is extended by things like roads, rivers, logistical organization, etc. Some improvements would be quick to build, such as basic shelter, simple farms, construct primitive weapons, etc. Others would take longer, build fortification, build advanced bridge, etc. Then other actions could be to use an existing building/improvement: such as to construct complex weapons.
So you start the game with a dozen or so GoPs. These you can spread around, but since multiple GoPs 'breed' faster when they are together, you would be encouraged to group them. But having a larger number means you can start scouting more and gaining more information about the world around you.
GoPs that are armed as soldiers aren't as effective at other tasks, but would take a few turns to train even if a weapons stock pile was already made for them. This would limit people from going "All soldiers, all the time".
And since your settlements are flexible, you are free to shift your GoPs around the map as the game advances. Of course sooner or later you will start constructing buildings and such that take enough time that abandoning them becomes less and less effective, and eventually your cities become far more permanent.