+1 to the detonator button or make it that they are chained together so that when one goes off they all go off. Don't want him to be OP but when he is called for an assist you basically get no damage from him at all.
I actually like the detonator idea for any grenade thrower and the chain idea. If any grenade blows that is on a character blows they all blow.
Plus he is useless on offense against Yoda battle meditation as his only attack is a debuff which is auto resisted, can't do damage and if Yoda is lead also gives turn meter to the person attacked. If there was ever a reason for a skip turn button it's this