I thought it would be a good idea to add paintable faces to rust. It would make it easier to identify clan members and add a bit more customization to the game.
I think one of the main issues with facpainting is that, if it were to work like signs do where you draw your own design, it would increase the amount of data stored on a server.
Currently, every time you create a sign, the design that you drew is exported into a .png file (maybe jpg. I forgot) and saved to the server. That way everyone is able to see it. If you wanted customizable face paints, it would work the same way.
The other option is templates that you choose from that are installed with the game. Kind of like clothing. You have a limited option with what you can do, but it will help keep servers more stable.
I think face painting in general is on garry’s radar, so I’m kind of expecting it to happen eventually. It’s been suggested a million times. I guess we just have to wait and see!
Concept art for warpaint (on the face/elsewhere) was produced months and months ago. Character variation (instead of everyone being the same bald white guy) is much more recent. I expect it’ll still happen, for the benefits you highlight, but it’s not a priority at this point, and they’re first working on the in-game-painting tech with signs.