I've always really liked the concept of fury, and that would probably be a great reference for making a similar asm. Personally I think you would be forced to rely on the talk skill a little too much in the scenario you mention though. I think having one end of the spectrum be dedicated to defense and one to damage balances out the system a lot. When you think about it low faith/brave having higher defense makes sense actually, fear is good sometimes.
For high brave... they are reckless but show no fear in the face of danger, so they would be able to attack recklessly and without fear of harm, therefor doing more damage. They would also be less likely to worry about attacks harming them, thus end up taking more damage. Kind of like when people say you are either brave or incredibly stupid.
For low brave... they are cowardly in a sense, so they would be afraid to attack and would attack cautiously while fearing for their safety, so less damage. Not being as reckless and having constant fear in battle, they would most likely be completely focused on defense and would therefor concentrate on taking less damage.
Faith would work the same, except the faithful rely on their faith to god(s) or whatever their faith entails. Those who have little faith in a deity protecting them would probably be more defensive. I know I won't be walking into a flaming building without some kind of protection, because I don't think there is some greater power that will shield me from the flames lol.
