I believe they should implement a trading system but it should be equal trades like exotic for exotic, legendary for legendary. But I also understand why they won't put it in because it would completely destroy the RNG basis in the game, but even so I have friends on Xbox one that have 4-5 gjallarhorns but not an icebreaker or some really good weapon. One of my buddies got his second icebreaker at the VoG normal exotic chest but he doesn't have a gjallarhorn so I believe he would trade it in a heart beat. Some good things could come from this but there are problems that we would see in the future if the trading system was added in.