As is the case with most MMO like games there is a natural progression of old raids not being run as often as new ones are introduced. Some of us are still missing weapons from Vault of Glass, Crota, etc. My hope is that a vendor is put in that allows us to use the shards collected from the corresponding raids to be used to buy these weapons. Ever since I accidentally deleted my Praedyth's Timepiece due to not locking i have been trying to run it. As you can guess not many do as PoE is current content. Hopefully everyone is on board with this and Bungie can implement something.