Regarding massive ships, in High Guard size was one of the primary defenses of a ship - tonnage smaller than the weapon USP led to automatic crits.
In FFS2, lasers were limited in megajoulage by TL, so having enough armor to protect against lasers of your own TL is, in my mind, the dividing line between real military ships and auxilaries suitable only for interacting with civilians. As armor is a surface area thing, and surface area goes up more slowly than volume, its difficult to get enough performance out of a small armored ship.
I can see 'Fighters' on an escort carrier still being a thing for piracy suppression, but real military ships swat virtually unlimited fighters out of space, as it's real easy to build ~600 MJ lasers that fire every thirty seconds, and real hard to put weapons that hurt real warships onto a small craft.
Ian Whitchurch