There is some points....
Spellcasting Penalty: We don't yet know how the penalties work. It may be that heavy armour has a significant spellcasting penalty
Stealth: Armour affects stealth - The stealth perks only provides a 50% reduction in the armour penalty. Heavy armour WILL always be a lot noisier than light armour.
Sprinting: Faster stamina recovery means you can sprint more often and for longer - light armour is the choice of mobile characters and mobile they shall be.
Overall it seems to me that a sneaky character, a hybrid caster, or a nimble marksman will all benefit from using light armour - roles where armour's actual ability to STOP hits is secondary to your role; trying do that stuff in heavy is a liability. Of course the balance IS firmly rooted for heavy right now, at the very least they need cut heavy's weight/movement reduction perk from 100% to like 50% - heavy armour wearer sprinting at the same speed as a light armour wearer is silly