Ol' Aulakauss has a crazy theory: I don't think Raid Weapons and Armor are going to be rendered totally useless. Yep! You heard that right, in spite of them explicitly and in no uncertain terms saying that all your Year One Legendary Are Belong To Us. They're overhauling Destiny and going out of their way to rectify things they done goofed on in Year One. They're also selling a bundle pack with Dark Below and House of Wolves in it, which would be a good way to piss a lot of people off when they find out the two extra DLCs they have are basically a playable version of 'Look how much worse it used to be!'. I'm going to go out on a limb and guess that they're going to add Level 40 versions of Vault of Glass, Crota's End and Prison of Elders, as well as have them offer relevantly rated Raid Legendaries and Raid Armor when played on these modes. Trials of Osiris and Iron Banner will obviously also be offering Taken King adjusted gear. So, while all your shit is going to be useless, I don't think you'll necessarily never be able to bring Fatebringer to bear again or run into combat with Black Hammer. I think you'll just need to re-run those Raids to get TTK-rated versions of them.