Although I have never wielded it, I know it is overpowered, even people who own it contend that it is too powerful. Every week, people get upset that Xur sells horrible stuff, but every week I am thrilled. I work hard to find exotics, and almost never allow Xur to give me one, it ruins the fun of the game. Not only that, but people cannot go around with an amazing gun and people think "Wow, that must have been hard to get!" They think "There is another Xur item." If Xur sells Gjallarhorn, one of two things will happen: It will be nerfed to mush by Bungie, who watch their content get destroyed by a weapon that should never have existed in its current form; It will remain un-nerfed, but lose all of its wonder and mystery, everyone will have one, so no one will care. Content will be ruined under Gjallarhorn's power, and Destiny will cease to be a challenge. You have a problem with that, go ahead and leave the "You just upset you don't have one" comments, but I know there are plenty out there who will agree with me.