Looking at this, and just wanted to stick a couple of thoughts in here.
It's a building game, but building is just for the sake of building unless it's one of these (thinking in programming terms here):
1) Building to block something from passing.
2) Building a path to reach a goal.
3) Constructing a machine.
A big problem I see with the RP layouts is that they reward gathering. Gathering is gameplay that has nothing to do with building, and it gives a deadline in the form of a resource limit. On the other hand, if we focused on something like farms for resources, players could construct "machines" to generate the resources they're going to use. Preventing spam would be pretty easy, in setting up the rewards for the most efficient constructions, as opposed to the most quantity of constructions.
Basically, instead of focusing on grabbing a plot, putting a box down, and then going out and grabbing as much as possible, the players should be focusing on building useful objects up to certain spam-suppressant limits, and in between builds, the players should be rewarded for maintenance on what they've already built.