I think it's rather pointless. Certainly, you would not be able to repair an item passed what a fief could produce. So it would actually be less useful than everyone makes it out to be. I have recently had my army in numerous battles, and had to transfer off excess gear within my hour of immunity, and as nice as it would be, it would actually be a seldom used feature. After every battle, I would have to give the gear back to my faction mates, and have them sneak into enemy villages to repair captured gear. Any of my damaged gear would have to be carted back to our homelands to be repaired.