I think a codex with audio files, accessible in-game, and can be viewed immediately or at any time, would be huge in creating an immersive Destiny universe. Yes, its not original, and has been done before by Mass Effect, but it gave the Mass Effect universe a scope that was incomparably larger than most games that rely on story to define a plot and setting. A first step in increasing the immersion, which story and lore can create for a game, is to attach the player to the story/lore in the most accessible way possible. While this will not address the loose story that was presented in the initial release version of the game, it could create a connection among the player, the missions, and the universe as a whole.