I think it's a question of scaling, and establishing an ambiance; you'd have to give a reason why navies aren't pushing the boundaries on ship displacements.
I like the Clement Sector setting where ships over a certain size have a chance of the 'Zimm field' collapsing, a real deterrent to building large ships.
By amending this slightly so that larger ships are possible at higher TL's it's possible o convert the setting to the Traveller universe.
Kind Regards
David