Lets talk a bit about what I'm planning for Oro.
I've flip flopped around with what I was planning due to various things seeming either too difficult or just not fun for me to continue to work on. Huge simulations would be possible but cause burn out. So the game has to be focused, at least the majority of the time, on the direct player actions in the small scale. However I still wanted to have some aspect of base building and expansion and stuff, so I went around and researched systems that have that sort of thing. Closest I found was that of "No country for old Kobolds" which has a system that is...Well I'm taking ideas not that system.
The general premise is that players control the town as a group, Choosing what to do with it, what buildings to make, what to research, etc. The town will be planned out on a grid map, much like what you see in Revolver. Doing this for 2 reasons: First because limited space can force choices and specialization. Second because if we have base invasions, It will be more meaningful if its on a town map you planned. What sort of things will be researched and constructed I'll still need to thing on but standard upgrades seem a viable idea; and a way to help newbies not be underpowered on spawn.
Population will determine town level, with new inhabitants coming to join the town as it grows or if you rescue them or do certain things. This will also be the player pool you pull from for playing, so if the town population bottoms out, then no more people can get pulled. This effectively means that losing too many people delevels the village, so the ability to through endless hordes at a mission is evened out somewhat by the fact that it's a phyric victory. Part of the town management is the concept of "Needs". The town has needs, and these needs take the form of dials that slowly tick down until they are empty. It can be simple things, like water or food, or more complex things needed for a specific reason. Like, say, supplying your forges with a specific kind of metal to make that new gun. Whenever you get a new building, you get a new power or upgrade but a new need as well. People dying and other failures cause those need dials to tick downward and if they hit zero, things start going very poorly. Threats are another dial that works similarly, but they go up as you succeed. The more of a foothold you make in the world, the more attention you draw. And attention can be very dangerous.
The game will mostly be mission based, where you are sent out with a specific goal, generally something that either refills a need or allows upgrades or lowers a threat. I still haven't figured out if I want a connected, consistent world or one made of instances. XCOM is instance style and its the easiest. It also allows for most variety because I can just do whatever. Connected means we have a set up map that you expand outward on. Its nice in that it allows for things like outposts or patroling areas or returning to places as things change and the like. But its also more difficult to set up because it requires a fair deal of forethought.