Would have thought that it would cost a small fortune to get one back in service again, and then add on top of that, the 1000+ crew requirement & running costs for such a large ship & perhaps, as much as your Marines want one back in service, it won't be financially viable.
Maybe a better solution would be to build something along the old monitor lines? Smaller hull, single turret & a lot less crew required. For these reasons, & being a modern ship, it should cost a lot less in service & may stand more chance with the folks who control the purse strings?
A lot less firepower than an Iowa certainly, but maybe the GPS shells being more accurate & modern autoloaders could do something to offset the reduced number of guns on the ship?
Here is a link to some photos of British Royal Navy monitors from the First World War. Not a patch on the beautiful lines of an Iowa I grant you :)