I lean towards that there should be more thought put into the various weapons that go into "turrets" and how much space they take up as a result.
For example, a laser turret--a single mount for simplicity--really needs no turret whatsoever. It could simply be a lens that is movable in the side of the hull with the necessary power feed, etc., between it and a fire control station and the power source. The FC station could be dedicated or part of some other control point, like on the bridge operated by the pilot, navigator, sensor operator, etc. That would be a function of the level of fire control used.
Plasma and fusion weapons would be more problematic. You need the projector for these along with a way to create the necessary plasma. That could get roomy PDQ.
Missiles could vary depending on how they're packaged. The equivalent of a VLS system without reloads would be more compact than a moving launcher with a loading system and room for human intervention in this process. Sand would be the same way. Why bother with a turret at all? Simply but the canisters in a fixed launching rack on the exterior of the ship (possibly streamlined on the hull if necessary) in positions were, when launched they create the necessary cloud of protection. That is, similar to chaff launchers on a plane today.