The problem is that they make powerful weapons too accessible like having Xur sell it for 23 strange coin. I can solo the weekly on hard with 2 lvl 29 and already have 18 Strange coin. Maybe stop giving Xur weapons to sell and start selling energy/asendant shards to level up instead? Raise the price of weapons? There's still a lot that needs to be worked on in regards to how you aquire weapons and Gear in this game.