True enough in real life, but how would you convert that to videogame format?
That's a game mechanic question, and is up for debates of course. The effect of armor in games are not particularly realistic when you think about it either, so there are options. From the way ti was done in Morrowind - you simply had a default armor class on every part of your body that was activated when you had no armor on it, to something new and interesting, since I'm quite sure devs woun't be implementing it the way I think of it, I'm not especially bothered with building a "system" - the option should be in, it's Bethesda's job to think of how you do it so it'll be fun.
What I'm saying is that it's logical to have, has an audience that wants it and is important for role playing certain kind of characters.
Oh, and about "combat system" I'm not an action player, I don't want to be bashing the keyboard and pulling combos, that's why I'd rather have a passive skill than have to learn to masterfully dodge, fighting is not the top of my list when playing RPG. Right now it's easier to be armored to the teeth paladin player skill wise, than a mage, which is just not right. I assume people who select warrior classes like the fighting part of the game better and will be better at it, so it should be the other way around.