Layers..
One usually also doesn't wear thick cloths under armor as it simply can get _very_ hot inside an armor.
Hold the phone here. (sorry for picking your one statement out, Kerol). It seems as if there is a misconception on armor in general. It is not a base for everyday fashion. Not was, not is, not ever will be. It was only worn when it was needed, or for pompous events.
Reasons:
1: We will start off with part of the quoted statement. Armor is hot. Very true. Even thin leather armor is hot. Ask any Biker. They will tell you.
2: "One usually also doesn't wear thick cloths under armor" Very false. The base of all armor (especially plate and maile) is a good thick coat of padding. Without this padding, maile is next to useless, and plate not much better. It is the armor that catches the edge, but the padding that softens the blow. Wrap a mellon in some maile, or a tight fitting piece of steel, then hit it with a hammer and you will know what I speak of. Even a helm has a good inch of padding that goes on first. All this padding is hot. Refer to reason #1.
3: Weight: Armor, even 'light' armor, is heavy. Plate can weigh close to 70-100 POUNDS (sorry to the metric folks). That takes a lot of power and work to heft around all day. Work makes you tired and hot.
4: #1 + #2 + #3 = hot + hot + hot. Ok, now add in the factor of sweating in a non breathing enclosure... 3 X hot X sweat= you guessed it, BAD smell. And after wearing it ALL day? Very bad smell, and a breeding ground for festering diseases. Why do you think the ladies all carried scented handkerchiefs back then? Ya... not to mention all the heat can kill very easily...which creates another smell all together that we will not go into here. It is not unknown for soldiers to die just from the heat, rather than an enemy blade.
5: Simply put, cost. Only the rich would wear plate armor, and not even very often. Maile iwas very costly also. Much of the armor we see from that time was for jousting and tournaments. Useless in actual battles. With a proper (and cheaply made) neckhook, knights (nobles mostly) were peasant fodder. Once hooked, a person in heavy, hot, smelly armor becomes completely defenseless. The true power in medieval times? Archers with minimal armor.
So, that is the argument against wearing armor all day long as the fashion. It is simply not practical, or sanitary. Many of you will say. "Hey, this is just a game!" Hmmm. True, but it is a game aimed at creating a virtual world, not a get-the-best-armor-and-baddest-sword-you-can-and-hack-things game. It is to be different from the hundred or so games that do that already. However, there is a good argument for it as well. No one wants to have to try to put armor on right before a fight. Lots of folks complain about just having to draw their weapons, as if is hard work.
Now, I do have a suggestion. Do something different. Don't wear armor all the time. *gasps are heard* Oh yes, you heard that right. But it is unrealistic to put on and take off armor before and after a fight, as doing so is not an easy task in the first place, taking a half hour -at least- to get all the gear in place, and the help of a comrad or two.
My solution: Wear normal clothing. Have an assortment of clothing options that would dazzle even the best of fashion gurus. The, when danger is near, do the He-Man thing. Hold your Glyph of Righteous Armor in the air and shout "I have the..." er...you get the point. Cool flash of special efects, and there you are in all your shining glory. Hail to thee... now go kill somthing befor your spell wears off.