My one big worries about space legs is, that they implement exactly one kind of gameplay there: pew pew.
There are enough good FPS out there, where the game is all about running around and shooting at things. I just disbelieve that EDs space legs can really compete with the good ones. There's too much of other game to work and improve, a sole focus on a new first person shooter mode would do no good.
So I actually hope the FD doesn't waste time and resources on building yet another FPS, but rather focus on other aspects. All in all, I personally mostly would hope that space legs give the game some social aspect which the "everybody is glued to the chair" gameplay just doesn't provide.