I'm all for the idea, the concept, and your proposed execution. Truly, it's quite well thought out. My only gripe however, would be in agreement with ungod. Replacing a principle shouldn't reward you in my eyes, it should have a price that must be payed.
An example if I may. I myself do not use tokens, a self inflicted law from a self inflicted wound a decade old. I picked principles that felt correct to me, of me, by me. This led to a uniquely my own set of principles, and they were not optimal for token fueled combat. If I had the chance to change and pick them all over again, however, I would be hard pressed to pick the ones that are "the best" for combat. Double anti freeze from two separate tokens and insane buffs all around.
I'd be tempted to replace a set of principles that is dear to me, literally makes up who I am as Fang (a literal mirror of myself but in this world) for an unbeatable upper hand in combat. And that worries me. Call me a fool for worrying that temptation would get the best of me but... if the option to change my principles from "me" to "power" is there, my morals and ethics would battle with my inner need for stacking the deck in my favor.
I know in my heart I'd be 90% inclined to keep myself as I am, but I'd do so only after obtaining the armour set you suggest here if it were implemented, since my crippling OCD and Completionist nature dominate my conscious mind. I like the idea. It's a great one. I just think wed need to pay a price for this ability, instead of being rewarded for being rewarded.