Players are already able to build these types of building with the new architecture parts. This idea does not have anything to do with tribes. This is something specifically for crafters, thieves, etc and the like. Ok let's think of it like guildhalls in say oblivion. you had your fighters guild, thieves guild, different crafting guilds.
Now out side of that, the other ideas that i see in this thread could also have a place, but i believe with the original idea at hand, i don't see how assuming its this when it hasn't even been implemented yet. Let's let those creative juices flow and try not to attack something that may bring folks in before it even starts.
B_ulam i agree with you and thats why the choice of where and what built would be up to the players. But this system should be outside of the tribe system as players shouldn't have to join a specific tribe just to be in that guild.
DDT I like the ideas you have set up and let me point out that right now since expansion isn't there yet it would still need to be owned by a tribe or person giving them full right to everything you own if you leave it there. With my proposal it would eliminate things being stolen. Now since no one owns them as well think about how fun it would be to siege for them
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