Not sure it's as overpowered as it seems... Each point of armor only has a 1/6 chance to soak a point of damage, and if they don't soak it all the armor gets damaged. Plus, Willpower seems like a precious resource, and if you spend it before your attack roll it might not even be useful. We'll see how it holds in playtesting, but I would try it raw first.
My concern on the other hand is that armor is really cheap. A full suit of plate is 1GP... Isn't plate armor supposed to be custom-made really expensive stuff?
You can build up to 10 WP from pushing rolls, and I believe it ends up being a very fluid currency (I have Mutant Year Zero but alas haven't had a chance to play yet). Maybe not enough to spend on each combat but available enough to spend against heavily armoured foes. 10 lots of 1/6 chance of soaking some damage is pretty good, an 84% chance of scoring at least one six. That then goes to a 0% chance against anyone that activates this tier 1 talent.
Usually I wouldn't bring out the big bad black knight until late in a game as a mega-boss, but now I would likely not bother to give heavily armoured foes unless I want the PC to pick-up some new armour!
I agree, the costs all seem quite low, the modest expensive melee weapon is a two-handed sword at 3 GP and Heavy Crossbow is 6 GP
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