I wear 7/7 heavy, and when I encounter a Bathrobe user it seems like they have 10x the armor that I do, I know they hold block because their life depends on it, and most likely stack shields but they shouldn't be more of a tank then someone who prioritizes in tanking.
A bathrobe user that stacks shields should have that same defence as base heavy armor. Get rid of the passive in light armor that grants spell resistance. Medium armor doesn't get a single defense buff, same should go for light armor.
Make it so those who wear heavy armor have higher spell resistance then those who wear light, get rid of the 7% bonus weapon damage and give heavy armor 7% damage mitigation, and also take away the spell resistance on light armor and give them something like increase max magicka.
~Thallen~