I don't like the idea of trading. While you don't really earn anything in Destiny, it's much better finding something through RNG rather than say buying it from xur. Imagine if trading was implemented. You could instantly acquire all the weapons you've ever wanted within no time at all. What would be the fun in that? You'll miss out on that great feeling you get when you finally see that Gally drop or any other coveted weapon. With more weapons and different rarity levels maybe; but with current Destiny I don't want to have anything to do with it.