I kind of wish it had an airship counterpart. Inflating a dirigible there would take advantage of the same atmosphere + gravity benefits with the added bonus of not needing constant power to move around.
Good point: I seriously wonder if they considered a dirigible design. Buoyancy + directional propulsion does seem simpler in my space-novice opinion compared to a quadcopter. A blimp would be slower than a quadcopter, but nobody's going to be piloting the thing in real time, so that shouldn't matter.
Yes, that was a mission proposal years ago, a blimp and quads. It was not selected then or rehashed this time. In addition, a blimp only concept has been floated (ha!) as well.
Blimp only wouldn't be able to take ground samples easily