Xur is never going to sell the Ice Breaker or Gjallarhorn. Well, I shouldn't say never, especially with the DLC coming out, but there's a high probability against it. Think, every time Xur sells a weapon, OP or not, what happens? Everyone buys it, everyone uses it, and it eventually gets nerfed. Bungie is probably doing you a favour. Those with the said weapons, congrats, you get to keep using your good weapon without worrying. But those without, If everyone hand Gjallarjorn and they nerfed it, it wouldn't be the Gjallarhord everyone wants. It'd just be another weapon. Lets all make peace with Xur and his sales because he probably is doing us more good than harm.