According to the blog post, “most” Faction vendors will soon sell specific Faction armor and weapons for Legendary shards and Faction tokens.
Earning the shards is simple, too, as Nightfall strikes, Faction Engrams, and dismantling Legendary gear provides more of the item.
Currently, Legendary shards have few uses, with Guardians infusing them with Legendary gear to raise its Power level or treating it as currency to buy materials from Xûr.
While many areas of the game were covered, from XP mechanics to a new weapon class, a large portion of the blog discussed how Legendary shards, Faction tokens, and Reputation tokens will be used in the future.