"Evasion:
Shroud yourself in mist to gain Major Evasion, which increases your dodge chance by 20% for 20 seconds. The effect of this ability is in pvp reduced for each part of medium armor missing by 5%."
So if you have only 2 pieces, you can use this skill but only with , 5% , 3 pieces you get 10% , 4 15% and 5 the full 20%
Thats balance ...and not the *** you are calling for "nerf heavy, buff this ,....pls i want my *** being op" And if zos would finally do this kind of method with all abilities you can play in a game close to real balance. But balance patches are not give any money to them, so you need to deal with it that you will see like 1000 more shop mounts and such thing before anything major happen.