I think the charm flexer is... Interesting :P In The Lost Hero, Piper had the charm speak ability without being too OP, and her charm speak could actually influence people to do things instead of just stun them. 

(( omq I just really want this guy in he would be awesome comic relief and the interactions between him and Kellen would be priceless ))

I mean basically this guy can't do anything offensively because he can't hold a weapon, and he would be extremely vulnerable to bullets, arrows, etc. Maybe he could only use the weapon-nullification ability on melee weapons, and only when he touches them with his hands. So like if he was snuck up on and somebody held a knife to his throat, he would be vulnerable. It's hand to hand combat with swords, daggers, etc., that he can protect himself, but he can't actually make offensive movements himself. Also, perhaps he could only use the ability on weapons harming him, so that he can't go around turning every sword into roses. 

Just some ideas?