Might be a moot point anyways if the melee/brawlers are Hired Guns - that Dangerous Covenant Signature Ability is down right deadly for minions and rivals, regardless of whatever skillcheck and destiny point requirement the talent will have.
But keep in mind that as the group gets more powerful and kills more enemies, if somebody in particular is sending those enemies, they can have a better idea of how powerful the group is. That means stronger enemies with more powerful weapons and tougher armor. But you could also just start slapping a few ranks in Adversary on some enemies, which upgrades any incoming attack.
EDIT: Also, it's probably easier to really challenge a Brawn-based character with stun damage.
Edited by Lathrop, 13 February 2014 - 10:55 AM.