There is no point in trying to flank a ship for example if doing it doesn't make you less open to attack from it's turrets.
Weapons point forwards 9 times out of 10, and a majority of people do put them up front act as a buffer (power regen, jumpdrive, thrusters, and shield regen are all more important when losing blocks). When you flank a ship, they can't fire their forward guns back until they turn around, which is normally their main DPS source. If you manage to fall from the turret fire alone, you're probably just outclassed.
People have already said that most people would just shove a stick out through the front. If you manage to blow off that end, you've probably also made a hole large enough that they can fire from that group of weapons leftover inside. 'Tactics' in the sense you are thinking about is shooting out the computers, which tend to be around the core or bridge from what I experienced, so if you can flank them and get their shields down, you
can shut down their weapons with a well placed shot to the weapons control center.
I don't see how it becomes a challenge either, it more of a annoyance than anything. From the ships I have seen, the weapons are right behind a thin layer of decoration at the front anyways. People would move 1, maybe 2 blocks, and everything would work again. It just creates an ugly looking (and potentially wide) bow with dozens of outputs dotted across it, what unless you snipe off the end with a cannon (good luck with that) you're still gonna have a functional weapon. It changes nothing except how ships would look, and screws with how a few people build.
As a final sidenote, the dreaded 'borgcube' that people say hidden weapons support. Death cubes generally did not have much, if any, hull to start with. A death cube is a blob of systems, with the weapons generally being up front because that is how everyone builds. People put weapons at the front and thrusters at the back or in areas where they would make sense, because our brains will go "this is how a spaceship works" even if we know it doesn't matter.
As a side note, I was under the impression that turrets could not fire through their mothership, in fact I know they can't cause I have seen the turret fire at weird angles so to not hit it. So no idea what you are about with turrets., this is a thread about the ship's onboard weapons (The ones you control while in a ship), not how turrets work.
TL;DR - The concept here would not make anything challenging. It would not add depth. It would merely annoy the people who try to make things look nice, and maybe piss off the few people who hide their master systems in the back.
The main opponents are shipbuilders
There is more than just shipbuilders here, and one of the few shipbuilders here even voted for this idea I believe. Vanhelzing pretty much said it was pointless, and he's a shipbuilder who builds his guns exposed as part of his ships. Try using an argument instead of trying to devalue those who don't agree with you.