I was thinking about a neat dlc and I will probably make a forum post about it, but it basically has a trio of guardians play through the story (matchmaking included) on mercury, fight the vex to take back the planet. The vet's use for the planet was to use the solar energy from the sun to hurl mercury towards the traveler and wipe us out with it. Could even come up with a new solar type enemy. Even the strikes and raid will have a part in the story to have players more engaged.