I have what I feel is a great idea to add replayability to the game. So as of now there are emblems that track kills for certain NPCs such as callus or the barons but there is no reason to get that kill count up. What if they added legendary/exotic cosmetics such as ghosts and sparrows that have a low drop rate on these kill count NPCs. When the item drops, a stamp or seal can be placed on your emblem showing other players what Kc you got that item. To give an example, give the barons a 1/500 chance to drop a sparrow. If a player gets that sparrow on the 120th kill, that number can be place at the left or right hand side of the emblem and some sort of symbol can be placed on the emblem to show that you got the sparrow at that kc.