My guess is that Bungie will not want to do this because people will be less encouraged to get the new gear. Whether or not this is true, I think this is a sticking point. I think a good idea would be to suggest that the VoG weapons be upgradeable in the near future (maybe after a couple of months). That will give the Crota's End weapons a chance to shine, but it would ensure us that our favorite VoG weapons would eventually be their equals.