Origins of names rarely square with common-place usage, so Naval terms are no different. And maybe blame Weber - he loves using Dreadnought as a class in the HH series.
And besides, what would you call something bigger than a Battleship?
Super-Battleship sounds silly, while somehow Superdreadnought sounds bad-ass.
I will say the idea of Destroyers being smaller than Cruisers always bugged me. A Destroyer should live up to its name, and have firepower only second to a battleship or bigger.
What worries me more is what Rank structure will Space Force use? Since they're coming from the Air Force, their ranks will be "baked in" at the start. But the second there's a space-Ship to command, you want that person to be a Captain ... Colonel would just sound way off.
And for that matter, what Air Force terms even are there for Ships? -Fighter / Bomber / Fighter-Bomber / Tanker? None of those work!
I think that in origin classification had meaning and should do for the future.
Main article: Ship types of the CultureClass / Acronym / Description
General Systems Vehicles / GSV / Mobile habitats and / or factory ships, largest Culture ship type. May be home to billions of people.
Medium Systems Vehicles / MSV / Smaller versions of the above. Sometimes former GSVs downgraded as larger GSV classes were developed.
Limited Systems Vehicles / LSV / Smaller versions of the above. Sometimes former GSVs or MSVs downgraded as larger GSV classes were developed.
General Contact Vehicles / GCV / Contact-configured GSVs; Mission-identical to GCUs (see below)
General Contact Units / GCU / Ambassadors, scouts and light transports; also main warship in peacetime
Limited Contact Units / LCU / Smaller versions of the above.
General Offensive Units / GOU / Dedicated main warships
Rapid Offensive Units / ROU / Dedicated fast warships
Limited Offensive Units / LOU / Dedicated warships, smaller than GOUs
Demilitarized ROUs / (d)ROU / Civilianised ROUs used as courier ships, all or most weaponry removed
Very Fast Pickets / VFP / A euphemism for (d)ROU, used in the same role.
Heavy Lifter / HL / Dedicated materials mover, smaller than GCUs.