Regarding Monk stances, I agree that raging should make Monks uncentered, similar to Paladins can't use their stances with any kind of rage. I'd go a step further and extend that Monk Stances don't work other classes stances, but that won't fly.
As for Deflection, you need to also include Shields in the discussion. In fact, any change to Armor needs to take shields into account also.