Instead of a 3rd faction, just introduce the "engineer" army unit that can do his work on Camps and then Outposts after the upgrade.
PvP will have a "+" here too i think. They (players) will get angry if the "engineered" forgotten are not visible to anyone else :tongue:
I mean... players got angry over much less then this... just do it !
Will be fun for all once it is properly introduced i guess... low level players would (those that start late a world) would at least have a workaround to catch up to some decent level.