There are few things I look at. First is modern networked sonobuoys. There are a few launch options which might work in the mission bay. Certainly bolt on processing or storage are possible.
The secondly and not quite proven tech yet but possibly more important... Anti Torpedo Torpedos. Processing, launch platform etc...
Third is like you stated UUV or USV. Launch and recovery along routes.
Fourth is UUV/USV modern decoys.
I think there are some other ideas in the hopper but that's what my Sat morning brain remembered.
As discussed above by Underway and I, it could also be a window into future ASW. An UUV with good AI programming that would travel near the surface and stream a tail, then pop up an antenna to report to its frigate when it "hears" something would give the frigate multiple tails from which to triangulate, making it possible for the helo to pin down and strike at the submarine that more faster and easily with a much lower consumption level for expendables like sonobuoys.
Yes there will also be missile attacks on Western forces but the USN has ships specifically designed to counter those attacks. If we feel that we need to up our AAW capability then as
@Furniture says we should get a dedicated AAW warship (highly unlikely due to money/personnel constraints) or look at other ways of increasing our missile capacity - most likely through minimally/unmanned arsenal ships - rather than tinkering with the CSC design.
Sonobuoys launchers, anti-torpedo torpedos, UUVs, USVs, arsenal ships, SOPD, VESTA... etc... These are all GREAT ideas.
But you know what these all have in common? Most are unproven systems, but
all of them are systems
not currently part of CSC.
Mk41 VLS, and all the missiles associated with it (except SM-3 and SM-6),
are part of the plan.
All your ideas sound like great CELEX upgrades, or maybe technology inserts for a later batch of CSC.
But we won't have that batch of CSCs online for the coming war; we'll be lucky if we have
any online for the coming war.
The most realistic thing we can do is simply
add more of what we already have lined up in the pipe; it's too late now, thanks to our abysmal procurement and ship building process, to insert totally new technologies.
So, build the fist batch with mission bays, because that's the only way we'll get them on time.
Build the next batch with additional VLS and NULKAs (or whatever the offboard decoy is going to be).
Heck, don't put the VLS along the sides like I recommended before, put them in the center, and put two more boats on each side.