Short version:
I agree with Braben on the sequential order of how this is going to unfold. Planetary landings on atmospheric astronomical bodies should be prio 1.
Long version:
Space legs is however the one immersive thing that binds the immersion together with imagination. Why you ask?
If you can see your fellow crewmembers as you have your VR on, interact with them as a real person from both your real eyes, the immensity, immersion and imagination ( III ) forms a complex illusion that forces your brain to accept it as fully real. Ponder the situation as you see Han Solo and Luke Skywalker chatting in the cockpit. Now that could be reality for Elite Dangerous in the near future. Full immersion. No difference between reality and the simulation. ( except the VR helmets ). Most importantly, the scale and the scope of that reality, it will, not only blow your mind, but blow your dreams away.
Now that is perhaps not the point with a little space shooter game, but it is a dream for experiences. And I mean that literally. You can use such an environment for far much more than just swooshing through space with your friends. You can do actual work in reality with such technology. And that is not a small thing at all.
FD is on the virge of doing just that. A fully immersive VR enhanced 3D representation in space and time. What would not a surgeon do to get a set of VR vision goggles and practice performing surgery on a body that resembles a whole universe in its entirety, with all the bloodvessels and systems that interact and communicate in real time. Or an engineer, building new constructs with his associates all over the world, in real time, in the same time and space.
So, spacelegs is important, for the future.
I looks like all play and fun to most of you, but this technology is hardcore stuff for real. There is no end to the possibilities.