Baffling really that it's not there. Make it really expensive. The most expensive thing in the game currently is that ship from Petra at what, 17.5k glimmer? Make the Etheric light cost that plus one each of the radiants, and ten each of the ascendants, and some coins and motes for good measure. The speaker exchange was a very good step in the right direction to sinking some currencies, especially Friday when Xur sold the helm engrams and now that most everyone has a couple few weapons they want to re-roll. Why not just add the Etheric light? If we are really honest, the point isn't just hitting max anymore (and thankfully so) but putting together a setup with both the perks and looks that suit your play style!