Accessibility is a key theme, as well. You don't have to worry as much about needing to play specific game modes to boost your Light level, and you won't need a key to recover loot from the Prison of Elders. Clearly, Bungie realizes that Destiny's progression system is still somewhat convoluted. This isn't the same as a full-fledged sequel (that isn't coming until 2017), but it might give you a reason to come back if you burned out the moment you hit level 40.