Now, obviously, there needs to be something to make sure Heavy Armor is physically limiting in some regard, otherwise everybody would be running around and cart-wheeling in the stuff, but at the same point, the current usage of Heavy Armor seems to be ‘put it on your Thrall or get out’.
Would it perhaps be possible to increase the ‘jump’ range of the Heavy Armor by perhaps an additional half of the current range without it becoming game-breaking?
Alternatively, adding a resistance to what other posters have called ‘posture damage’, meaning that wearing a full set of heavy armor will make it far more difficult for enemy players and/or hostile NPCs to break your attack-combos with their own, could make Heavy Armor viable again for PvP and PvE usage for players.
This is the heavy armor, where you’re sacrificing agility and mobility for sheer, overwhelming staying power. Yes, you will be hit more, but the ability to endure heavy blows, shrug off crippling hits and even outright ignore attacks that would penetrate lighter armors with the damage reduction that comes from Heavy Armor, especially the Flawless and Exceptional Tiers, should be adequate compensation.
Light armor is trading extreme vulnerability for superior mobility, where you’re counting on not being hit at all to keep you alive and being able to out-run and out-flank your enemies.
Medium armor is a trade-off between the two, granting some added protection and the ability to weather hits with limited ability while not completely surrendering your ability to reposition easily in the middle of a fight to avoid an AoE or Cleaving attack that could easily kill you or severely weaken you.
Heavy Armor should, in theory, be admitting you are going to get hit, you are going to get hurt, but your ability to stay in the thick of the fight and deliver punishing damage in retaliation is unmatched and your ability to resist being knocked around or your combos stalled is greatly reduced.