I voted nay.
It's very clear to me, that those "stunts" that are effecting powers, should be add-ons or power options, but no "mortal stunt".
While a mere mortal could use every mortal stunt in YS, he couldn't use a stunt, that would effect the speed of his shapeshifting f.e. because it would affect a power he had to have, which would revoke his status as a mere mortal. Thus it couldn't be a "mortal" stunt anymore.
You don't have to be a mortal to use a mortal stunt. They're called "mortal stunts" because anyone, including mortals, can use them. Why would you need a separate stunt affecting powers (e.g. Claws) when the character has already bought a stunt that affects his use of the skill they're based on (e.g. Killer Blow affects the use of Fists)?