Of course, a decent monk needs to be able to dodge, which isn't really supported in the game, but would be a good mechanic for all classes (armor reduces dodge speed, heavier armor more). Monks should have some kind of "Iron Skin" perk to increase armor, though IMO it should be less effective than light armor.
For Monk, Dodge could be built on the Light Armor Perk that allows you to avoid damage. To make it something more robust than simply "you have 25% chance to dodge melee attacks," again build the Perks on Stamina, hell, build the entire class upon strategizing and regulating Stamina/Magicka usage.
Want a higher % chance to dodge attacks? You need more Stamina. But want to deal more damage? Higher damage moves cost more Stamina. Etc, etc.
