I think the title speaks for itself. They provide +1 Stress on unarmed attacks. That's it. As a Mundane Stunt you can get +2 with a restriction...which makes it about equal to Claws. But aren't powers supposed to be flat-out better than Mundane Stunts? Shouldn't someone who just has the Claws power (and, say, Human Form at +0) get something a bit more for the 3 Refresh they gave up?
To look at it another way, Inhuman Strength grants +2 Stress (which also applies to Weapon attacks) and at least one Refresh worth of other capabilities (+3 Lifting and Breakin, +1 to Grapples, +1 Grapple Stress). Shouldn't claws equal the Stress bonus since that's all they give, and even then only to unarmed attacks?
Right now, claws are something certain concepts (like say, a werewolf) require, and so are purchased for them, but at least to me, it feels like a chore, a wasted point of Refresh to make the concept work. That shuldn't be the case with any Stunt, much less a Power, and almost acts as a surcharge subtly discouraging those concepts (not that that'll stop people, but still).
Changing it isn't even particularly unbalancing since you can only get Claws once, so it's not gonna stack up or anything (well, it'll stack with Strength powers, but those are more expensive).