my personal preference would be for each piece of armour to have 3 factors in its makeup
1. material eg iron, steel etc
2. type eg plate, chainmail
3. style eg Elven, Nordic, Orcish
each material, type & style would have different properties
eg plate protects better against slashing and piercing weapons, chainmail better against blunt
Elven would be light, give less of a penalty to speed, but be less durable, Dwemer would be the opposite
Absolutely - without a doubt. There should be fundamental differences between chain and plate, for instance (and should be mid-range combinations of the two). Better or worse protection against various types of weapons would be a great addition. And I love the idea of different styles of the same basic materials - Orcish steel would be particularly well made, thus durable (they are held to be the best armorers in the realm, after all), while Nordic steel would be solid and practical - maybe a bit better protection, not quite as durable but a bit easier to repair. Elven steel would provide decent protection and be relatively light (and have additional abilty to be enchanted, if variations between materials make a return, as they should), but would be less durable and less protective overall. And so on. And there needs to be a similar range of cloth/leather "armors" with their own pluses and minuses. Extraordinarily light, not a lot of protection and actually a bit more durable, in a sense. I've never been satisfied with the notion of leather armor "breaking." Plate can break. It should take quite a lot to accomplish that, but it can literally break. Leather can't break. It doesn't matter how many times you hit it with a blunt weapon - all that's going to do is scuff it. Cutting it would obviously cut it, but then it's still leather armor - it's just got a slice in it. It would obviously be less effective, but it's not going to "break."
I went through Morrowind years ago and changed lots of things about the armor, just to get them to balance. While it's nice that there are as many options as there are, they still don't make full use of them. Light is the most obvious one - there's really just about no reason to wear anything other than chitin, then glass (or, with Tribunal, DB, then glass). I made it so that chitin still provided better protection than netch, but was actually a bit less durable, so netch is actually worth wearing if you're concerned about durability. Newtscale is more durable, provides about the same protection, but has much higher enchantment potential. But it weighs more. In mediums, bonemold is very durable, decent protection, lighter than it was by default. Adamantium provides better protection but is actually less durable while weighing about the same (almost all of the default medium armors are too heavy), Dreugh is relatively fragile, but quite light and has a high enchanting potential. Nordic chain is a bit heavy, very durable, decent protection. And so on. What that did is make just about every armor item in the game worth wearing, just depending on what the character valued. Want light weight and high enchantability and willing to trade off protection? There's an armor for that. Want maximum durability and decent protection and willing to trade off increased weight for that? There's an armor for that. Want maximum protection and relatively light weight and willing to risk lower durability? There's an armor for that too. That's how it should be.
Hopefully that's how it will be.