heavy armor vs light armor?

[adeyke]

One other advantage is that sometimes good armours simply happen to be heavy. If a unique/set armour you want to use is heavy, there isn't anything you can do to change it.

However, there's no intrinsic benefit from heavy armour. So, if you magically changed an armour from light to heavy, without changing anything else, you'd be going slower and losing more stamina, but wouldn't get any benefit.