Zeal. The nonmagical paladin... is crazy. Their religious fervor lets them tap into their body's full potential, breaking the limits the brain pus on muscle.Without some supernatural aspect, what's the difference between a nonmagical paladin and a fighter, mechanically? Serious question. I'd like to know where your head is at here.
Sorta like the monk but less discipline and more "So lawful stupid you are unstoppable".
Probably going back to the old mechanics where the avenger had to target certain enemies in order, except you choose the order and you get bonuses if you stick to those targets.
This is a system where Rage isn't barbarian exclusive. 3 martial classes would have rage but use them in different ways.