Why does a base have to be symmetrical in design?
I have seen this as a point in many base design guides (no one makes it compulsory, but stress it highly).
A symmetrical base is equally strong on all sides, but also is equally weak on all sides. In fact, by making base asymmetrical, an attacker is forced to think faster about all sides in those 30 seconds, rather than just focussing on one side (because all other sides are similar).
Another point can be the circular range of turrets, but unless the building is dead centered, this point doesn't hold.
so, why this stress on symmetry?