I recently bumped into this game called northgard. It's in early access and i noticed it had similar mechanics to 0ad in some ways. The territory concept is the same, and a lot of the art feels like the Gauls or Britons. I have played it for an hour now, and it is quite different to 0ad, but can't shake that feeling that it is somehow similar. Anyway, it wasn't really my type of game, but here are some screenshots and maybe if people are interested in gameplay ideas, check it out.