Well if you think a 57 mm can do what a broadside of 5 t inch shells can do, we'll have to disagree.
As for hull size, private rooms for the women sailors takes up space. And you can't free up enough space by removing the armor.
Today's Arleigh Burke class destroyers have the displacement of a WWII light cruiser (8000-10000 tons).
That's about the range of a pre-dreadnaught battleship.
As for hull size, private rooms for the women sailors takes up space.
Arleigh Burke was laid down in 1988.
That's about the range of a pre-dreadnaught battleship.
The increase in hull size from pre-Dreadnaught to Iowa or Yamato was accompanied by a corresponding increase in gun size, with little change in the fundamental technology of the guns or sighting mechanism until the very end. We now have ships of the same tonnage but totally different armament and mission.