I'd expect something higher than the "10%" for avoiding damage. The heavy armor perks still seem much superior, I want light armor to be on par with them. Basically you can run and sneak just as well with heavy armor with perks, and you also benefit from the better armor rating. This is Oblivion all over again.
One out of ten hits does you zero damage whatsoever. If it was more than that, say 50% or so, it would be overpowered. And no you can't. Heavy armor produces more noise than light armor produces more noise than wearing nothing. It's not linked to the weight, it's the category of the armor that matters. And heavy armor will still impede your stamina regeneration a lot and consume your stamina faster when you sprint in it.
You'll be slower and noisier overall in heavy armor no matter what. In return you get a much higher armor rating. Sammu was wrong, the scale for improvement is in increments of 30%. I didn't see the other perks but I wouldn't be surprised if he was wrong about that one that makes heavy armor not weigh anything.