I know lots of people talk about bringing back the battlewagon; and there's lots of argument about it just would be a floating sailor's coffin.
But, like the way aircraft precision strikes and ground support would always be carried out by fighter planes, now unmanned drones fill some of these roles. Why send a gabillion dollar plane in harms way, not to mention endanger a pilot, if a drone could do the job? It's a niche player. Drones are deadly, hard to see, even harder to shoot down, have no pilot, and relatively inexpensive.
How about a niche player warship? I'm not suggesting a disposable battleship, but I'm beginning to think there may be a niche for a similar type vessel; call it a modern day ship-of-the-line. It's main role would be to free up missile DDG's and CG's for roles where they are sorely needed, without losing any punch. A junkyard dog with a mean bite. Why use an expensive missile when a large naval shell will do nicely? How many shells did a battleship used to carry for its main guns -800? 1000? That's a lot of relatively inexpensive, very destructive power; how many missiles does a DDG carry? 70-90? Cost per each?
The ship-of-the-line could be outfitted with modernized but conventional guns/turrets, in 15'' or 16'' calibre, or rail gun technology thats coming. Not much additional development cost there. They would use the same auto loading and central firing principle that the Salem class cruisers had and used with success. The only other armament needed would be anti-aircraft weaponry. And if the old BB Missouri could accurately hit something from 24miles away, I'm sure its not out of the realm of possibility to attain ranges of 40 or 50miles for modern big guns. Modern technology and computers reduce crew size to the same or less than an Arleigh Burke destroyer, another cost savings. Propulsion diesel or combination diesel/turbine; another cost savings not sacrificing speed or range.
For defense, they would use existing anti-missile and anti torpedo decoying tech. No development cost there. They would be heavily armored, as a battleship would be to withstand their own size calibre weapons and resist missile hits without being mission compromised.
The vessel would function in a marine amphibious assault and support function, similar to the aircraft carrier spinoff with the Wasp-class ship. As an added role, the ship-of-the-line could function in fleet actions with carrier battle groups as necessary, or in a smaller group centered around herself for commerce interdiction/blockade or anti piracy sorties.
Instead of building these gazillion dollar zumwalt destroyers when you have the likes of the Arleigh Burke-class ships around, just build a few of these ships of the line.