I'd thought of that as well, and am in agreement there. A few random comments/thoughts/concerns, though.

1) This is pretty much EXACTLY the idea behind Gates of the Forge. I assume this will be tweaked, but will there be any idea changes to the legacy, or will it end up being more just a "cumulative" effect?

2) There are a lot of subsets of classes that seem like they would be rather fitting for certain armor use. I don't quite agree with orcs needing bone armor in general, but think it's fitting for Shig-ru, and that stone armor use would be fitting for Mamlauks.

2a) Similarly, it would be kinda cool if Enigma warriors could gain mystical armor use.

3) I know we've got bone, metal, and then light armor includes hide and leather, but I'm curious where, if anywhere, some other materials fall. Wood being the primary one that seems unplaced. I'd rather doubt things like wood or scale to generally be very light. Also, things like gems and crystal...would they be counted stone, or just oddities not added anywhere? I assume these items are still usable, just similar to parrying without having the parry skill.

4) The "brains" idea was an idea for something that would help with your "make int/wis maybe be useful". I still like it

5) Yeah, I think I'm out. General coolness. Should be fun.