They just need to let us trade among people in your fireteam for a couple of hours after an item drops. For example, I finish crota and I get a Black Hammer and one of my fireteam members gets a Hunger of Crita.Both items have a two-hour timer to trade it with your fireteam members ONLY. So if I already have Black Hammer and want Hunger of Crota instead, I can trade it to the person who has Hunger of Crota. And after the timer expires, you can no longer trade it. So this way, Bungie doesnt have to worry about ppl abusing trading system and also promotes the social aspect of this game because you would most likely run raids with your friends to trade.