Would it not be simpler to just have a level 40/290 raid added; They have just released a hard mode for Kings Fall, which does just that. You get higher level light *supposedly* of pretty much the same gear from Normal mode. Implementing that into a 'Nightmare' mode to the old raids would give you higher light armour/weapons... Although I think something in the next DLC drop would give us something like Ethereal Light that will enable us to bring that gear up to this year light level - Of course you would have to be level 40 and light 290 to obtain it and thus need to purchase the new DLC along with Taken King in order to obtain said 'thing' we get what we want, Bungie/Activision get more money... Um, kinda Win/Win?