I think you're right in that generic settings won't do much to attract players so much as just not scare them off. All the good settings, IMO, are recognizably fantasy but have some sort of critical distinction. Dark Sun, Planescape, Eberron, Spelljammer, Shadowrun--every single one of these has swords, magic, elves, and dwarves, but they're certainly not what you might consider generic fantasy.
Personally I think FH's sweet spot is going to be mid- to high-level fantasy. Mythic Greece, for example, or Malazan, or Charn, or even Bas-Lag. Ultimately I think Hero would be best served with several 'boutique' settings as you describe, but right now there isn't even one that's set up to use as a starting point.