Re: Playtesting is the judge. . .

I would be opposed to allowing any player or any NPC to use Agility for defense against a slugfest / melee /blunt / edged attack Fighting feat roll unless they are declaring that they are Dodging that round (removes an action). But that only yields up to -6CS (red result) to the attacker's Fighting feat roll (decreasing his chance to hit). Make sure to make your players realize their characters are wetting on themselves and scampering for cover when they do this. Against a punch. Or a lead pipe. Whatever. There's a reason being a better at FIGHTING makes you higher in HEALTH in MSH.

Make sure to explain to your players the difference between Dodging (Agility-based) and Evading (Fighting-based). Evading is for your fighters that can take a punch if they have to, successful evades open up better attacks next round [*], with the added bonus that you acheive the desired effect of "dodging" (not getting hit) without all that fetal-position please-don't-hit-me look in your eye.

Face it. Agility in combat is for shooting and throwing, not flinching.

[*] - a house rule of mine allows players with sufficient speed powers, martial arts talents, or raw Fighting ability to allow extra attacks per round to sacrifice one of these attacks for an evade feat / attack feat combo in the same round.