I would also remove the mid turret as it only destroyed the ship it was on more than it destroyed the ship fired on.
Turrets like that were actually quite popular throughout the dreadnought era
That`s true, many bbs had them but they did cause more harm than good. The hull had to be strengthened taking up valuable space and weight, the magazine in the middle takes up space that could be used for extra engine power or armor and the blast and the shockwave from the guns could break more delicate equipments such as rangefinders, windows, binoculars and even damages the ship it self when fired. You also have to take into consideration the poor firing arc. These are just the cons I can come up with quickly. These cons are also present with wing turrets.