It's a viable strategy to mix and match plate and cloth armor to have a chance at resisting nasty things like Knockdown and magic debuffs. So equipping a lot of cloth will give you better resistances against spells and other nasty effects, like poison.
Cloth armor and robes generally gives better magic resistance in Divinity 2. And the best part is that this might actually work. You can outfit your tanks and fighters in nothing but cloth and wizard robes if you want to. Instead you can have your entire party kitted out in full plate armor wielding great swords and battle axes.
Unlike a lot of other RPGs, Divinity: Original Sin II does not require your casters such as wizards and necromancers to wear all cloth armor.
