So far we have chased the Vex through time, slain a rising Hive god, and shackled a rogue Fallen lord. We have sifted through the ruins of the Cosmodrome, wandered the silence of the Ocean of Storms, and hacked through the jungles of the Ishtar Basin. So when do we get to go back to Mars? We understand the Cabal presence to be some (abandoned? forgotten?) task force of a much larger alien army. These hyper-militarized juggernauts have taken an interest in human innovations and Vex technology. As I recall they were present at the Battle of Twilight Gap; they may have even fought alongside the Fallen, though I doubt there's much of an alliance there beyond the accidental. I think a good place to start for such an expansion could be a battle with the Cabal on Earth. This will, of course, require putting a whole palette of models in a place they haven't previously been used, but what a surprise that would be. A whole mission spent going from hot spot to hot spot in the Cosmodrome, destroying Cabal landing parties, all as a timed event. In fact, the week preceding the expansion's launch could be spent with similar Cabal assaults occurring on Earth, the Moon, and Venus. With the Tower once again reminded that the Cabal exist, the fight would shift to Mars. I want to believe there is some currently blocked area connected to Tharsis Junction, and of course there is the whole land tank to explore. The story could focus on subduing the Cabal forces on Mars, perhaps ending with a Cabal raid that tasks guardians with entering the land tank, disabling whole portions of this massive vehicle (weapons, communications, powerplant, etc.). Thoughts?