This is one thing I don't like about dresden... stunts not-withstanding, they seem to have pigeon-holed their defensive stats a little much. I'd like to see more than one skill come with a NATIVE defensive trapping.
Or perhaps, have a house-rule that lets players choose 2 defensive trappings- with the standard build being Athletics:Dodge plus either Weaponry:Parry, Fists:Block or Lore:Counterspelling at player's choice, +1 more per stunt.
Each would have to be at least a little limited in application based off context...
Athletics:Dodge (or Performance:Dance?) represent you being hard to hit, and work against pretty much anything as long as you're free to move around; Lore:Counterspelling would primarily be for defending against magic on the fly, but could also work against most mundane effects as long as you see them coming; Fists:Block and Weaponry:Parry mostly for anything close enough; Guns:Gun Fu might represent shooting things out of the air, or defensive cover fire; etc, etc. There's no reason you couldn't build a stunt to add defensive trapping to any skill you want, anyway... just instead of including one for free (on athletics), let them pick it.
Anyways- short answer... I'd be ok with letting fists act defensively without a stunt... but I'd prefer a house-rule like above.