I wrote "with their own root" so that they don't decay.
If they have a small amount of territory outside their own space, then it's possible to build towers or whatever else that gives more territory, and then you don't need a Civic Center/Kleroukia.
So way overpowered imho (except maybe in rare balanced maps : trying to build something there could be a strategic objective, while the opponents have the strategic objective of preventing other players from building it).
edit : oh, maybe you meant the P2 garrisonned tower or whatever that I proposed ?
For that too the balance towards resource gathering is hard to find, as I wrote in my original post.