I think the one thing keeping heavy armor down in pvp and most pve is the effectiveness of blocking with other armor types. Blocking depending on armor type should change in these ways with suggested numbers:
1: Increase the base cost of blocking by ~200 (stamina) and decrease the base block mitigation by 50% (putting it down to 25%)
2: For light armor, make no changes.
3: For medium armor via 5-piece trait, decrease block cost by 20% and increase block mitigation by 10%(increasing it to 35%).
4: For heavy armor via 5-piece trait, decrease block cost by an amount that would make it 5% above current normal 5-piece heavy armor blocking amount, and increase block mitigation by 15% which would be 50% blocking mitigation, the current normal.
5: For 1h/sh: Reduce the block cost decrease by 5%.
End effect is to maintain the current level of heavy armor 1h/sh blocking power, slightly increase the other weapon/heavy armor blocking power, and reduce the blocking effectiveness of dps armors.