I'd also note that from what it looks like, Mortals are capable of dishing out the badassery too.
Point of fact being Murphy. While she gets pushed and knocked around, she certainly is in the middle of the action in a lot of cases. She has no powers, just her akido and gun.
Same with Marcone. He faces down the Loup-Garou and Nicodemus with knives and a rifle. Being an exceptionally talented human who just gets dropped in with all the magic may not suddenly give Joe Schmo great powers that he has to deal with, but now you have someone who's At The Top of Their Game suddenly realizing they, the big fish in the pond, are really just a little fish in the sea. And yet they still contend with the big predators.
Or if you prefer, Mr. Martial Arts Instructor or Mr. Average Priest who gets dropped into the middle of a supernatural conflict and realizes he has to survive. And where Mr. Priest believes in god and the power of miracles, he never would have realized he has the power of Faith magic on his side that he can literally wield. And Mr. Martial Artist who just thought he did this for defense now is stuck having to apply it to more difficult challenges than a mugger.
I disagree with your assessment of the wizard as a viable character for my specifications. Though an individual's power may, initially, be far from what it will eventually grow to be, the realization that such power is within one's grasp may bring about the sort of psychological alteration that I seek in a character. The differential between the normal, mundane life and the supernaturally inclined life would be more than substantial by that actualization alone.
You may have a point with regards to a full fledged Wizard. But consider the likes of Victor or Kravos, who were mortal men who just discovered later in life that they had a gift, and thus mutured it slowly on their own, with no one there. Harry called them "talented amateurs". It's possible that someone could be walking around with a gift, and not know it, and only after being exposed to something, start looking for answers and finding it. They may not have the full potential power of a Wizard, but they might be a one or two trick pony who can learn a few things.
Because remember, the werewolves really got one trick: become a wolf. In the grand scheme of things, that's not that impressive or powerful. But it's useful. So ultimately if they can do one or two things, but do them well, does that fit your definition, or would you classify that as a weak secondary character who's less interesting? Because I think a character who stumbles across the ability of say, an Ectomancer (someone who speaks/deals with spirits) may not be useful all the time, but he's great for recon, and information gathering, and maybe indrectly useful in combat. Not every character needs to be a heavy hitter, but merely a contender. Sort've like how in D&D no one wants to play the cleric or the bard, because they're "support" roles. And yet, a character who gains these abilities could likely change - even the smallest thing like the Ectomancery, the character could summon the ghosts of relatives of his co-workers, just to find out the dirt on them, so he can spread rumors.
