As almost always, I want to less complexity in the rules, not more (aside from optional rules).
So while I think that your ideas for adding resistance to armour types (which already exists through enchantments, though) might be a cool optional rule, all I think we need for armour types is a list of the ACs, attributes, and cost, along with a list of some options that might typically fall into the AC, and then let players and DMs use their imaginations. Is your AC 16 coming from chainmail or from some weird combination of scavenged chitin plates and rubber bands? Who cares?!
I think the same for weapons - do we really need separate entries for things like "long sword" and "battle-axe"? Just have an entry for "1 handed slashing weapon" and let players fill in the rest.