Bungie gave Xbox exclusives. It was called the Halo franchise. I'm not saying that what you are proposing is a terrible idea. I'm merely pointing out why Xbox players don't have any exclusive content. They made the exclusives for PlayStation because a huge playerbase could have been missed by PlayStation players. So Bungie made a deal with Sony in hopes to sway more PlayStation players to buy into Destiny. Kind of a 'buy our game because we're going to give you some cooler stuff and we cool' sort of thing.
lol, actually Xbox users don't have any exclusive content because Sony dished out a ton of money for Destiny to have Playstation exclusives. It doesn't have anything to do with Halo or Bungie's past. It was a deal made between Sony and Bungie/Activision.
I'm just saying a year is way too long to wait for content. Most games are a month or a week. And then to say "nah, a year isn't long enough let's make it two" is just ridiculous.