I think it would be a great idea. However., like the vault, your player can use a weapon if it's your level. To combat "cheapening" the experience, the gun cannot be traded for a gun 2 levels higher or lower, and cannot be an exotic or vanguard weapon/armor. That would fix it IMO. It would come in handy, say you get an AR and your friend the SR and you both wanted the other's weapon, it would be fantastic