I'd come back for atmospheric landings - doubt I'd even bother reinstalling for spacelegs - what's to explore? the same dead worlds we've had for 5 years, the same 5 identical space stations? Unless they're bolting on a whole new game along with it, that isn't a spaceship flying game?!?
I could understand adding legs after the game's complete, just to keep it going... but there's still no comets, landable asteroids, usable gas giants, improved ice worlds, actual caves, improved rocks scatter system (mentioned once by Fdev), interactive (no matter how short) black holes... and still only two planet types to land on.
I did nearly 2000 hours flying around in ED so what's spacelegs gonna add, 40 hours?