So Barbarian* and Thief are stupid names, even though they tell the player what the character is about, simply because they "aren't something you'd call yourself", but Rogue, which is a pretty vague and meaningless name in exactly same way Fighter is, is a good name? Even though again, I can't see anyone calling themselves this in describing what they do. "A dashing rogue" is unlikely, in D&D, to be a Rogue, either. More likely a Fighter or Swashbuckler (or Warlord in 4E). I mean, a Rogue only means "a guy who steals things and stabs people in the back" in D&D. In general English, exactly like Fighter, it has a very different meaning.
I think your logic there is a bit horrible tangled and confused.
Personally I think Thief and Barbarian were/are good names because players go "AHA that's what I want to be!" when they read it. Same for Cavalier or Knight (but lots of players are then disappointed that Knight isn't actually particularly interesting as a class). Better to keep class names as useful identifiers, and have characters role-play their self-description. I mean, a Fighter MIGHT describe himself as a Warrior, a Soldier, a Mercenary, a Protagonist, or just a person. Generally speaking, only characters with distinct magical powers or highly specific social positions (which in many cases are a result of their magical powers) would use their class name to describe themselves, anyway.
* = Due to awareness of Conan the Barbarian, at least.