How possible is it to implementing Armor Ability Trees?
Instead of combining a variety of pieces to form the ideal weight combination just change it to all light, med, or heavy. This would not only make certain items more desirable (light chest for example) but also allow the benefits to be build on the set instead of each piece.
They could work the same as weapon ability trees except all passive and only get the benefit when in that specific armor set. Heavy Armor tree could focus on Defense and Damage reduction while the Light Armor tree could focus on damage and evasion. The Med armor tree could have options for both but less effective. (For example in the heavy tree you could point a point in 10% damage reduction, in the Med tree that would give 5% damage reduction, and no option for it in the light tree.)
IMO this would make balancing easier in the future but adding, removing, or adjusting the passives in each tree while allowing players to customize to how they would prefer to play.