[hunvagy]

Well if it's a misc skill, then training your heavy armor will not make you level up. That can be good or bad, depending on how fast you like your leveling. But it also won't add options to the attribute increases on level up. If I recall correctly for Morrowind, raising major skill contribute to level up, and raising minor skills contributes to the points you can add to the governing attribute on level up. If you're a mage, or the like, you shouldn't be using heavy armor anyway. Just because it's heavy, it's not better. The Tribunal armor (medium) has better end game statistics then daedric armor.