People complain about Impenetrable being too good for PvP, the problem is most other traits are lackluster when it comes to being useful in both PvE and PvP settings altogether. Here are some ideas to improving the quality of other armor traits to be useful throughout the game, the values listed are arbitrary to give an example of the potential they can provide.
Sturdy - Item takes 22% less durability damage, and reduces Armor and Spell Penetration against you by 1%. The increment per item quality is 0.5% up to 3% per item at legendary quality. That can give a total of 21% reduction to Armor and Spell Penetration against you.
Reinforced - Increases this item's Armor value by 4%, and increases damage mitigation when blocking by 1.5%. The increment per item quality is 0.75% up to 4.5% per item at legendary quality. That can get you a little over 31% additional damage mitigation when blocking.
Well Fitted - Reduces the cost of sprint by 1.5%, and reduces the duration of snares and immobilize by 3%. The increment per item quality is 2% up to 11% per item at legendary quality. That potentially gives you a total of 77% reduction to the duration of snares and immobilize effects used against you. With just 3 items you could cut down the total duration by 1/3, with full 7 items it drops that down to 1/4.
Exploration - Increases exploration experience by 6%, and experience gained from capturing keeps and resources by 4%. The increment per item quality is 1.5% up to 10% per item at legendary quality. This additional effect applies to PvP when you take over a flag at Keeps and resource nodes in Cyrodiil giving you a maximum of 70% additional experience taking over PvP locations; great for the leveling players and the new Champion point system you're planning in the future.