While I can definitely understand the lure of placing more and more guns on a guard post, the thought makes me uneasy for some reason. I think it might be that I'm seeing a slippery slope. I'm afraid that if structures end up being too powerful, we would effectively end up in an arms race with ourselves, trying to maintain game balance with increasingly more powerful units. In my opinion it is better to avoid that slope entirely.
Besides which, I feel that the gameplay of Outpost 2 was meant to focus on effectively managing multiple units with limited abilities. If we start giving one guardpost the offensive capability of two or more, then I think it takes away some of the coordination required to manage the colony, and hence some of the fun from the game.
At the far end of that road you would end up with a Civilization-like situation, in which all fixed structures are contained in a one-tile "city", and you issue a single command to build defenses around the entire city at once.
As an argument from a "realism" point of view, generally the more complex something is, the more fragile it is. Take for example a gun in development by the US military; It is the most reliable gun ever built because it has few to no moving parts, and thus very little opportunity to break or jam. The simpler and more straightforward something is, the more reliable it will be, which is invaluable during combat.
In a traditional Outpost 2 Guardpost, the entire structure essentially rotates to face the enemy unit, and a fixed turret fires at it. Not counting the systems in the turret itself, this is a total of one moving part, with motors driven by some simple targeting information fed directly from the CC, or possibly a simple computer if the CC is not connected. By contrast, a guardpost with 16 independent turrets, 4 to a side, would be a nightmare from a logistical standpoint.
-It would require sophisticated targeting software to run all the turrets, and the more complicated a piece of software is, the more difficult it is to debug, and the more likely it is to develop glitches/abnormalities under stress.
-Would each turret be completely independent? Would you be able to pack that much redundant systemry into 4 tiles? Maybe there are shared systems, like a central grenade feeder for all the Rocket Launchers or something, but I don't even want to try to imagine the mechanics behind something like that, or how easily their functioning could be disrupted. At the very least, if a single shared system goes down, the whole post does.
-Some sort of complex system of moving armor plates would be needed in order to keep the moving turrets from leaving gaps in the main structure. Once again, more potential for something to break down or jam.
-Guard posts explode when destroyed. What happens if a single turret in this post is destroyed? Does the whole structure go with it?
Finally, what is the point of having 4 turrets on each side. There are really very few situations when a single turret will be attacked from all directions. The original guardpost can already rotate, so it might as well rotate 360 degrees as 90 or 180, but would it be worthwhile to build a guardpost with up to 12 weapons that you knew had very little chance of ever facing towards an enemy?
The only advantage I can see to this is the fact that you could fit more turrets into a smaller space, but surely there are better/more efficient ways to do that?