Long time since I have posted here, but I recently thought of one thing in TES that is badly done. That is the armor system, not only are the names wrong, it also doesn't make sense.
We have the division between "heavy" and "light" armor, previously also medium armor. And think about this a little: the cheapest heavy armor you can find is a full plate suit, and it's very cheap. It's a full plate armor, making i out of some indestructible fantasy material is the only thing that can make it better, and that's how it's done. Light armor makes little sense, too, actually it only makes sense in the early levels. But then, look at this guy http://newwars.files.wordpress.com/2010/03/ancient_sasanid_cataphract_uther_oxford_2003_06_21.jpg that is a reconstruction of a cataphract, the stuff he is wearing would be called "light armor" in TES, and that's just stupid. Chainmail is heavier than full plate, just less restricting.
The division between the armor types, another thing is balance. In real life, heavy armor was EXPENSIVE, only the elite could afford full armor suits. But in TES you can just crawl out of the prison and buy yourself one. And that's why I think the current armor system should be abolished. When we have light and heavy armor skills, the classes need to be balanced, meaning we will have ridiculously cheap heavy armor and super-protective armor that weighs nothing(OK, because it's a fantasy world the super light armor is no problem).
Here's what I think of it: Instead of having equipment from 2(or 3) classes, there is only weight and how restrictive armor is. Because armor skill doesn't make sense in the first place, agility and athletics should be what makes armor movement more easy. That would be great for roleplay, you have the choice of what to do based on what you need. A normal adventurer wouldn't need more than a chest armor and some good boots, maybe. But if you want to be a tank warrior, you can get yourself some fully covering heavy armor. The current system makes it so that it's no good option not to use armor, and i you do, you better carry a full suit, just minimal penalties!
I agree that in real life full-plate was a sign of status and cost quite a bit. Understandably you might expect that it should then cost quite a bit, but this does not necessarily apply to a fantasy setting, especially TES. As someone else pointed out, in the past material was the main expense of goods, not labor. However, this is not the case today, with technology as it is. However, with a fantasy setting the world has access to magical means of producing various products, in effect replacing technology at least to a degree. This drives up labor, and down material acquisition. Then you have to take into account that better alternatives DO exist to steel full=plate in TES, where as they didn't in real life. This would drive down demand for steel full-plate because almost all of the magical materials are better. Since the demand for iron armor goes down, there's excess supply, excess supply means cheaper prices. So steel should be cheap, not because it was the TES equivalent of steel armor from real life, but because it was not. In real life steel was the most beneficial substance to make armor out of. In TES it isn't so the same cost does not apply in the least.
I disagree withe second paragraph, at least in part. Having an armor skill makes a lot of sense, in real life there were all sorts of armor masters, it was a discipline that Samurai often worked into. It was more than just trying to move out of the way. The idea was to learn how the armor takes the impact and how to learn to stand against a blow and move with it in order to provide the maximum protection to yourself, while preventing the most damage possible to the armor itself. It was quite a difficult discipline, and since you had to get hit to learn you could imagine few people survived to master it. So I'd have to disagree, because there is training/discipline component to armor mastery.
All this being said, I'm not sure I have a problem with changing the armor system or leaving it the same. I don't mind change but since I don't have a problem with it as is, I'd probably stick to a more "If it ain't broke, don't fix it" approach. However, I would like to see armor slots and enchantment abilities more like those found in Morrowind. I don't like how they made gauntlets a single item, combined "greaves" with the cuirass, and combined pauldrons into one item attached to the cuirass. In Morrowind I often liked the Aethestics of off-balanced armor. Plus enchantment in Oblivion was not worth it unless you used sigil stones, because there was no customization to effects and enchantments were too weak when non-sigil enchanted.