OK, you guys have won me over. I'm really starting to get into the swing of things now....
I'm thinking that instead of a single "flavor class" (heh!) level, the game system should be revised to allow a player to apply, say, 20 CDPs (Character Development Points) in any of the following areas: saves, attributes, skills, hitpoints, BAB, and feats/abilities.
The way it would work is this: when you gain a new character level, you retroactively declare which *previous* skills, feats, etc., will be considered "prerequisites" for the character level bonuses you're about to take now. Then you apply up to +2 CDPs in your save categories, up to +10 CDPs in hit points (each die size worth 2 CDPs, of course), up to +8 CDPs in skill points, up to +1 CDPs in BAB, *maybe* a +1 CDP in attributes, and any remainder CDPs in special class abilities like spellcasting or rogue sneaking. In that latter category would also fall feats and feat-like abilities of various value (CDP costs to be assigned later).
And furthermore, at each new level, you get to attach a new class title for yourself -- Elemental Mage, for example, or Variant Ranger, or Court Wizard, or Grand Poohbah ... whatever. Each level is by itself a "flavor class" (heh!).
This system would allow maximum flexibility and all the prestige class hooks you could ever desire. It's also the "flavor class" (heh!) concept take to its extreme potential, negating any additional silly discussion necessary in this thread.
You can thank me later after you get a chance to think about my brilliant plan.