So this Friday is game night and I realize I have to make a decision on the issues that were brought up in the first game session. As much as i like the idea of making armour a more abstract concept, I think that in the interest of playing fair with the rules as written I am going to just adjust the existing table and switch the magic penalty from the STR differential to the armour AC bonus. So the armor strength requirements are lower for everyone and arcane magic users will have a penalty to cast equal to the AC bonus of the armour (a leather clad mage casting a first level spell would need to spend 5hp (3+2).
So this table is what I'm going to use for the rest of the play test:
as suggested in the previous post) but still keep the strength mechanics and economic values in place so the rest of the rules aren't disrupted. I'll see how this works and see if it makes sense in the next draft to keep this or make it more streamlined. I also snuck in a little choice point in the medium armour bracket where chain costs less but weighs more. I do like those kind of things if you can keep them simple and not break things.