Thoughts on Magically-Light Armor?

[Dakota Mike]

Traditionally in fantasy settings, magical weapons and armor are often depicted as lighter than their non-enchanted counterparts.  To this end, I've been toying with the idea of adding magically-light mail armor to our campaign.  So if a wizard wanted to use an enchant armor spell they could either do the normal +1 enchantment raising the mail armor bonus to +3 overall, or they could instead make "magically-light armor." This armor would grant the normal +2 armor bonus of non-enchanted mail, but would only have the weight and encumbrance of leather armor.  The end result being that they would gain back that 1" of movement.  So a knight in magically-light armor would be move 6 instead of move 5.

This seemed like an interesting idea and would give players an additional choice when enchanting.  Was wondering what people in the community thought of this?  I am still weighing the pros and cons and trying to determine if this would be overpowered or could be exploited in some way I haven't thought of. 

[Philhelm]

There are already Boots of Speed that add +1 Move, so a Move 6 Knight is already possible.  +1 Mail Armor is valued at 400, while the Boots of Speed is valued at 300, so it doesn't seem unfair to allow weightless armor as a house rule.