I just got hit by some eureka moment, and thought: why not make the designs obey the actual purpose of the ship, instead of the other way around?
look at this ship:
picture heresure it's ugly,... but it wasn't built like a traditional ship, it was built to sail in shallow waters.
to do that, you need a smaller hull... with a smaller hull, you cant fit your regular amount of weapons... and if you don't carry your regular amount of weapons, you don't need your regular crew compliment...
so, scrap the surplus quarters and accomodations, and fit a bigger cargo hold and advanced computers,... and you got yourself a light attack cruiser.
now, they might not be firing rockets into land any time soon, but they surely pack a punch against anything smaller than a warship and against any coastal defences.
which is what they might be facing, since they're a coastal patrol
you want a carrier? fine...
which ship you want to carry and why?
what maintenance equipment you need to service that class of ship?
how much space does all that take?
how much does it weight?
what kind of power you can get out of your biggest engine?
how much space does that engine take?
....
well,... you get the idea