It would be interesting to see what would happen if the BBs were modernized. Put every ship system on the table besides one (or perhaps two) turret of the big guns and the hull armor, and see what happens. Redesign every ship system with an eye toward reducing the manpower requirement and automating functions, and see how many you would need to man a ship this size. Replace the engines with modern gas turbines. Eliminate as much of the ship superstructure as possible, to eliminate excess weight and vulerability. For every space freed up, put in a cluster of vertical launch missiles.
It would be interesting to see what the designers would come up with. It would probably be ugly as Hell, but it might be a formidable platform that could be affordable to operate.
You would have something similar to the Arsenal Ship and that was an ugly mother.
When Reagan first pulled them out of mothballs, plans were drawn up to do just that. They were going to pull number 3 turret, redesign the aft section as a mini-carrier for Harriers, replace the electronics and the the main propulsion, put in a VLS missile system, the whole nine yards. At the time the estimated cost per ship would have been close to a billion dollars so I imagine it would be several times that now. The brutal fact is that the Navy doesn't have that kind of money to waste on a platform with such limited use as the battleships.
Actually what you describe reminds me a great deal of the disastrous Japanese modification of the Ise and Hyuga during World War II.
Yeah... gut it and make the BB armored troop transport.. WHy waste all that beautiful armor.. BB is not your average tin can..