Good points.
Bah, I dunno. Skill, effort...maybe I'll just be vague. "Defends at Mediocre" would satisfy both readings.
And yes, attacking with Athletics is pretty powerful. One has to be careful with attack stunts, just as one does with defense stunts.
PS: Shrug It Off actually isn't just a nerf. It has the notable benefit of working against ambushes. And unlike other defense stunts, it never outright fails on you.