umm... I don't think they just pick any bass-ackwards name just because it sounds cool. There's always a seed of convention.
I think that "Cruiser-Destroyer" makes perfect sense.
Yeah, convention, as in, Star Wars convention. Of course I don't know that, I'm only guessing, like everyone else. Some people care about contemporary or WW2 parallels and some people don't. Do we know what sort of person gave the ships names? No, not really.
But seriously, does anyone think any large ship in sci-fi would be called a Destroyer if not for the ISD and Star Wars? Well I'm sure someone else would have continued the trend at some point, but perhaps not with the same impact. I think most large ships called Destroyer in sci fi are called as such because of the ISD myself.
Dreadnought is another seriously overused term. It's cool that FS2 went with Juggernaut instead (hmmn, was the Samatra a Juggernaut? Samatra / Sathanas . . hmmn. Maybe it was just a battle platform).