Honestly in a game like this, the dumbest idea in the world is not allowing item trades, at least it should be allowed in some form. Maybe have it where you can only trade items with someone who was in your fireteam when the item was dropped and only for a limited time, or maybe only someone who is in your clan, or on your friends list. There are plenty of ways to do it legitimately, I know if i am running with a scout rifle and my brother is running with an autorifle and a rare autorifle drops for me and a scout for him, thats some serious lame stuff when we cant swap em.