For me, each base class should have its own distinctive mechanic. Barbarians get rage, and associate rage-based powers and abilities. Paladins get smite and lay on hands, and abilities that build off that. Warblades get maneuvers. Fighters get, I don't know, dice pools. Playing a different base class should be a different experience. It doesn't have to be a complete subsystem, but a distinctive, overarching thematic power or two.
Why "noble" barbarians? I would reverse your evaluations of fighters and rangers. Otherwise, something like that, yeah.Quick class ideas:
Barbarian: Noble Berzerker
Ranger: Relyable master at arms/ Aragorn (Mixed in with Fighter)
Paladin: Knight-Errant. Light of the people
Knight: Knight in Shining Armor
Priest: Preacher of the faith, healer (cleric kinda steps (with a Mobile Launch Platform) on paladin's toes)
Mage: Learned Caster, Limited (as in to a theme, or to a school) in spells known
Sorcerer: Wild Caster, could have a Warlock (Trade for spellcasting) ACF
Druid: As usual, but no pet
classes i cant find space for:
rogue: kinda the same space as ranger
fighter: too much mechanical overlap with ranger
I've actually been toying with the notion of "savage" classes verses "civilized" classes. It seems to me that there are an awful lot of classes that can be paired up along those lines. Barbarians vs Fighters. Wizards vs Sorcerers. Clerics vs Favored Souls. And so on.