Have you thought about putting these weapons on a
mentioned above? It's the cheapest idea to go underneath the water at a fraction of the costs of a nuclear submarine with a similar abilty to cover range during deployment. Equipping it with artillery can give you a large railgun with abilities similar to
guns for ASAT with low probability of launch detection until only a short distance away and rapidly accelerating with a rocket engine once outside the atmosphere (with a high starting speed).
SMX-25 will be the alternative for all countries who want to have a submarine escort for their carrier, but won't or can't have a nuclear one (Germany, Italy, Australia?). Plus, it's the best littoral warfare concept in my opinion (modify Zumwalt like this for a few bucks) that can be combined with a gun(as precise, but much cheaper munitions than guided missiles) that endangers all platforms that otherwise can't shoot and scoot quickly enough to escape enemy detectors and their sophisticated search algorithms.
Plus, space is much less expensive than on a full-fledged submarine, especially of nuclear design. So this ship is best suited as a submarine missile carrier with an arsenal for many more lower value targets than the traditional missile submarines with nuclear tipped armament. This missile capability will likely be combined with commandos and UAV operating as scouts.
The nuclear strike missile submarine makes sense as the best second strike platform in a world where China and India make nuclear first strike a non-option and thus render the giant expensive nuclear arsenals of the Cold War antagonists irrelevant for their new world order. Nukes will be rather bottomless defence money holes than security assets, with their role increasingly limited to providing prestige.
The same arsenal distributed to small arsenal ships versus large arsenal ships means staggering costs because you have to buy several times the same capabilities for much less munitions. Steel is cheap, chips are expensive.
It's pretty generous of an enemy if he lines up high value targets for your arsenal ship to turkey shoot them. Normally, you have to knock through numbers of inexpensive assets before being able to strike the object you want to destroy. That's the reason why there is a
.
Another factor is that satellites are careful not to get close to ships that simply kill them ASAP with ASAT, much reducing their detection ability if you don't want to trade satellites for ships (both are expensive and limited).
Great input guys, makes one look at problems from many different angles and find unexpected things.