What can the Iowa and Wisconsin do that a carrier air wing can't?
Nothing beats 16 inch guns for shore bombardment.
The range of Battleship is limited, but then so is the Operating theater of air craft.
Just look at what happened in Vietnam, Look at all the aircraft lost.
While the New Jersey and the Heavy Cruisers Cratered the shoreline.
It is no secret that we have yet to come up with a weapon that equals the bombardment power of a 16 gun.
The Rail guns are very promising, but the navy has botched the Zummwalts, badly.
Congress in 2006 said this "In summary, the committee is concerned that the Navy has foregone the long-range fire support capability of the battleship, has given little cause for optimism with respect to meeting near-term developmental objectives, and appears unrealistic in planning to support expeditionary warfare in the mid-term. The committee views the Navy’s strategy for providing naval surface fire support as 'high risk,' and will continue to monitor progress accordingly." Evaluation of the United States Navy's naval surface fire support program in the National Defense Authorization Act of 2007[13]
Simplest is always the best, and few things beat a cannon firing.
But if you want something overly complicated and over budget. Get the Pentagon on it.