Dauntless wrote:the only problem with that type of ship is that it can only be used as a fleet/sqaudron escort.
most navies including the fictional ones like a ship that can be used for more then one purpose. The RMN has tried to stay away from designs that are so specialised, as they needed as many ships as they could build.
plus up against current threats (SLN) there is just no call for such a ship and that that is what the keyhole systems are for on the larger combatants.
For that matter, a ship meant to work exclusively near the fleet as a part of its immediate defensive envelope will need to be about as tough as the rest of the wall and won't need to be any faster. So that specialist missile defense unit ought to be built on a SD hull anyway, if it is to be built at all.
SD(P)'s with Keyhole 2 are mightily tough propositions. Making them tougher in a wall now is accomplished with an anti-missile LAC screen, but even those LAC's aren't strictly specialized for that purpose.
I suppose there may be a niche for a SD - non-podlayer - with an exceptionally beefy set of anti-missile defenses, a deep boat bay with more drones of various types even than a standard waller, a modest number of Mk 23 tubes (and perhaps some 23-E tubes), and a slew of Lorelei decoys to cover not only itself in the wall, but also other wallers and to give itself even more protection operating alone. The idea would be that it's a kind of dual specialist unit: an escort with the wall and a BC on steroids operating alone (or with a passel of DD's/CL's for a screen).
I suspect that's still too much of a specialist, and that the two roles are too disjoint for regular deployment. It's just less of an impossible sell.