So I know there are a ton of Khvostov posts. However I think with the addition of weapon manufacturers in The Taken King, that a update to the weapon could be worked in. There is a weapons manufacturer in game called Häkke which manufactures weapons that look more like our modern weapons in the 21st century. I think Bungie could add a small sidequest to make the Khvostov into a Legendary weapon. This quest would lead you to the starting area of the game and have you kill some small fallen captain boss (if you don't have the Khvostov it would drop again for you at this point). the second part would involve you gathering relic iron and spinmetal in order to 'remake' the weapon. The lastly you bring the weapon and the materials to the gunsmith who would then take the gun to Häkke and have them 'remake' the weapon into a legendary auto rifle with a fresh Häkke paint job and fresh sight. As far as perks go I would be fine with the ability to reroll or if Bungie could come up with some interesting unique stuff like on Murmur or Vestian Dynasty. I think this could be integrated fairly well with Bungie's new focus on Quests and would please the community who want to see the Khvostov make a return. Let me know what you think and upvote this post if you want to make it happen! I think it would be fairly easy to implement if we get the idea to Bungie fairly soon.