I've heard that justification before, but I don't believe it is true. Dragon Age: Origins had 4 different armor types and it didn't feel muddled at all. Each type had a distinct set of advantages and disadvantages.
I've heard that one before, but like you I don't believe it's true. For one thing, DA:O and Skyrim aren't even remotely comparable as far as gameplay goes. you don't feel the difference in armor in Dragon Age to anywhere near the extent you do in Skyrim for one simple reason: one game lets you control your character from first person, while the other doesn't. Dragon age armor only affects your protection rating, your fatigue costs, and your aggro rating. Skyrim, on the other hand, affects your fatigue, armor rating and movement speed. The difference is, you actually can feel the difference between armor types as you play.
For another, to use that specific example, medium armor in DA:O had NOTHING special about it. it was just a mix between light and heavy armor.
and yes, I have played dragon age origins.
Could you elaborate? I'm not familiar with those differences. As was said earlier, in TES games, the difference between light and heavy is movement/stealth vs protection. The probably with medium is that it sits in the middle and doesn't do either very well. That does make it kind of pointless.
here's a summary
light armor: least protection, most fatigue, least aggro
medium: more protection than light but less than heavy, less fatigue and aggro than heavy but more than heavy
heavy: 2nd most protection, 2nd least fatigue, 2nd most aggro AND its penalty on archery can be negated
massive: most protection, least fatigue, most aggro