Light - Mobility, 20% more Dmg, 20% More Healing, 20% Increase in Potion Cooldowns, 15% decrease in Health Regen, Exhaust recovery time increased by 50%, Backstabs Reduce incoming Healing to enemies by 20%, Reduced incoming healing by 20%, at 200 con - 10k hp
Medium - Skrimisher, 10% Cooldown on All Abilities, 10% Increase to Con Scaling, 10% Increase in Potion Cooldowns, 10% Increase in Slash and Magic dmg, 10% increase to stamina, Exhaust recovery time increased by 10%, Reduced incoming healing by 10%, at 200 con - 12k hp
Heavy - Tank, 20% increase to CC duration, 30% increase to Con Scaling, 10% Decrease to Exhaust Recovery time, 15% Increase to Health Regen, 20% Blocking Stability increase, 20% decreased Healing Output, 15% decrease to movement speed, 25% increase to CC recovery time, at 200 Con - 15k hp
This would make light armor users have a much harsher punishment for spamming dodges carelessly, as well as reduce the effectiveness of them chugging potions while being chased off to never be killed, This would push them into the role of being ranged/assassin/glass cannon playstyles.
Additionally, this would help make medium armor viable as the main skirmisher class without giving unnecessary buffs to some weapons that already perform well in skirmisher settings (Blunderbuss, Rapier, Spear), this would make skirmishers the Melee brawlers, the Mages, the Swashbucklers
This would make heavy armor Exceptionally effective at Tanking and Providing CC, at the expense of mobility. In combination with healers, Tanks already do not die, This would make them much more viable at their role of soaking damage as sponges. Additionally the reduction in CC duration applied to them would help tanks feel less like a ping pong ball. Possibly with some changes to the sword and shield to provide ally blocking would make them viable in a pvp setting.
All of these Percentages would be subject to change as AGS would have a lot more data from a ptr than my simple mind. This is just a rough concept.