Blue
Ravenous Bugblatter Beast of Traal
First, thanks for clarifying what "successful" means - I had opened this thread expecting things all over the place, but "do the best at meeting the intent of the class" is fairly unambiguous, and doesn't drag into "what's more powerful", it focuses on "where did mechanics do a good job of codifying the feel / intent". Because some of these are "more playable" (easier not to de-optimize), "more powerful", "more cherry-pickable", etc.
Focusing on "Crunch supports fluff", I'll rank them.
==Strong mechanical support for class feel
Beguiler - form and function work well. intent wants chr, gives social skills, and appropriate spells. mechanics delivers
Barbarian - rage, lots of HPs, simple options, big weapons.
Druid - druidic feel and abilities match up. Much better pairing on intent and mechanics then cleric.
Monk - monk feels very much like a D&D monk. Which is it's own thing, since a historic monk was something quite different.
Swashbuckler - good marriage between mechanics and movie swashbucklers. Not the best, btu that's because the mechanics were a bit weak so they couldn't support as well.
Paladin - code of conduct with mechanical support. heavily armored knight plus divine providence. Mechanics support intent.
Fighter - yeah, strong, lots of martial options. Lots of feats, which from a mechanics viewpoint made them very customizable to the fighter you want, so I guess that's a good marriage of intent and mechanics, even if one step removed.
Ranger - like monk, very good fit for a D&D ranger. If you want the arch-example to be Aragorn, you've got a good deal to allow that archetype.
Rogue - one of my favorite classes, but really making it a no-int needed skills monkey works from a balance perspective but misses out on a lot of common rogue archetypes.
Wizard - needs to be smart, is frail, casts spells, can have a familiar. Okay, not a bad fit. (And a dang powerful class at high levels.)
==Moderate mechanical support for class feel
Marshal - lots of boost to martial combat in it's area, though a bit awkward melding the workable mechanics and the special effect. Not a bad job.
Sorcerer - eh, it casts spells spontaneously through force of personality, and is bad at just about everything else. not a lot of mechanics to support the feel for the class. Not bad, just not overly generous.
Knight - meh. challenge mechanism didn't make them particularly feel knightly. Had a code of conduct with mechanical effects for failign liek the paladin which helped.
Scout - scouts are good at stealth and ambushing ... well, except that the mechanics force them to move around a lot. I understand where skirmish fits mechanically and how it encourages mobility, but going from that to some who is supposed to hear and see all, be a natural tracker, btu is supposed to disengage instead of getting into combat the fluff doesn't match. Reskin the class to something like "dervish" and then you get a blend of mechanics and intent.
==Weak mechanical support for class feel
Cleric - no one can argue not an effective class, but besides domains and choice of cure/inflict there's little mechanically linking them to their deities. It's not a fail, but it's not strong. (Unlike the class itself, which can be quite strong).
Favored Soul - even less then the cleric, and they all get wings. Huh? This is a mechanical line up for divine sorcerer, but little crunch/fluff line up.
Bard - the mechanical division between bardic music and bardic magic has never done a great job of making them feel like "our music is magic", even if I like playing the class.
==Skipped - sorry, never played with and don't remember enough about them.
Dragon Shaman
Duskblade
Hexblade
Warlock
Warmage
I have to say, you made me curious: what brings this question up? I found answering was pretty interesting to myself as a thought exercise.
Focusing on "Crunch supports fluff", I'll rank them.
==Strong mechanical support for class feel
Beguiler - form and function work well. intent wants chr, gives social skills, and appropriate spells. mechanics delivers
Barbarian - rage, lots of HPs, simple options, big weapons.
Druid - druidic feel and abilities match up. Much better pairing on intent and mechanics then cleric.
Monk - monk feels very much like a D&D monk. Which is it's own thing, since a historic monk was something quite different.
Swashbuckler - good marriage between mechanics and movie swashbucklers. Not the best, btu that's because the mechanics were a bit weak so they couldn't support as well.
Paladin - code of conduct with mechanical support. heavily armored knight plus divine providence. Mechanics support intent.
Fighter - yeah, strong, lots of martial options. Lots of feats, which from a mechanics viewpoint made them very customizable to the fighter you want, so I guess that's a good marriage of intent and mechanics, even if one step removed.
Ranger - like monk, very good fit for a D&D ranger. If you want the arch-example to be Aragorn, you've got a good deal to allow that archetype.
Rogue - one of my favorite classes, but really making it a no-int needed skills monkey works from a balance perspective but misses out on a lot of common rogue archetypes.
Wizard - needs to be smart, is frail, casts spells, can have a familiar. Okay, not a bad fit. (And a dang powerful class at high levels.)
==Moderate mechanical support for class feel
Marshal - lots of boost to martial combat in it's area, though a bit awkward melding the workable mechanics and the special effect. Not a bad job.
Sorcerer - eh, it casts spells spontaneously through force of personality, and is bad at just about everything else. not a lot of mechanics to support the feel for the class. Not bad, just not overly generous.
Knight - meh. challenge mechanism didn't make them particularly feel knightly. Had a code of conduct with mechanical effects for failign liek the paladin which helped.
Scout - scouts are good at stealth and ambushing ... well, except that the mechanics force them to move around a lot. I understand where skirmish fits mechanically and how it encourages mobility, but going from that to some who is supposed to hear and see all, be a natural tracker, btu is supposed to disengage instead of getting into combat the fluff doesn't match. Reskin the class to something like "dervish" and then you get a blend of mechanics and intent.
==Weak mechanical support for class feel
Cleric - no one can argue not an effective class, but besides domains and choice of cure/inflict there's little mechanically linking them to their deities. It's not a fail, but it's not strong. (Unlike the class itself, which can be quite strong).
Favored Soul - even less then the cleric, and they all get wings. Huh? This is a mechanical line up for divine sorcerer, but little crunch/fluff line up.
Bard - the mechanical division between bardic music and bardic magic has never done a great job of making them feel like "our music is magic", even if I like playing the class.
==Skipped - sorry, never played with and don't remember enough about them.
Dragon Shaman
Duskblade
Hexblade
Warlock
Warmage
I have to say, you made me curious: what brings this question up? I found answering was pretty interesting to myself as a thought exercise.