I hope there is no perk that makes heavy armour weightless if you're wearing it, that was stupid in Oblivion. What's the advantage of light armour if heavy doesn't weigh anything?
Yep, heavy armour is weightless from the very beginning. Wait... Oh, right, one still has to spend a lot of time to reach Master level of the skill and can possibly finish all quests and exploring without ever reaching it.
Oh, and Master Light Armor gives you 0 weight on equip and +50% more AC. What's the advantage of heavy armour if light offers the same AC?