I recon they should implement something that makes that every month ur account can trade 1 exotic, 1 legendary, 2 rares, 3 uncommons and 3 whites. This would mean that people that have a exotic hunter helmet they they don't want and they have a friend who has a exotic warlock chest piece you want, you can swap with them, but then that's it for a month. But I think bungie shouldn't allow swapping off items you find on planets eg spin metal.