I think what it all comes down to is that the world isn't reacting to us. The hive are infinite, just sitting in their broken fortress of the moon.. The fallen aren't advancing or being pushed back, regardless of the amount of Guardians that kill instances of Sepiks prime.. Why aren't there unique PVE events that happen that everyone can be involved in? A week long attack on the city on earth by the Fallen, during which you can see and hear distant explosions from the tower and you can get straight in on the action (fireteam of 6, maybe some sort of horde mode) and at the end of the week, we will either lose that area or gain it back?? Each has it's own advantages and disadvantages!! The world needs to be fluctuating, ever changing, that's why we're bored.