I've come to appreciate a small hangar on major warships if I don't have carriers as the centerpiece of my navy.
Modular sensor packages, miniature hospital ships (which could double at lifeboats; haven't yet run a comparison between cryo storage and short-deployment excess quarters), flag-bridge-in-a-box, box launcher pods, buoy/mine launcher pods, boarding shuttle, high-powered interceptor craft that can hopefully keep up with some of the slower missiles...
there is a great deal of stuff that might be mightily useful for a given mission, but which would be excessive to put on every ship.