I know this might be a stretch, as I am no current gaming tech expert, but would it be possible for Destiny to be "Shared Open Solar System"?
What I mean is- like seamless matchmaking- being able to enter any location without any loading screens or UI. For example, going from Old Russia to the Mumbai Push or even from Earth to Venus in your ship all in-game.
Perhaps this could be done using the same tech as with public events, but on a massive scale. The game world could be broken down into a manageable number of zones with each zone having several servers; crossing into another zone could be set up on the same basis as going from a private space to a public space.
Again I'm no expert so don't bother criticizing the question.