I just tested the Demo, and there are many things that need a lot of work. Sorry I'm more criticist than appraisal.
First good job in getting the shuttle more flyiable, unfortunetly we lost a nice feature it had, the booster....
Now tuckling the problem areas.
Noise and scale: the terrain in the planets has too much noise and the last is out of proportion. I explain : When you approach the ground from space, you realise that the terrain is noisier closer than in the distance. It will look more realistic if the ground, specially the mountains were smoother, all the nice noise we have closer to the ground would do wonders in the bigger land mass,... I think.... Elevation is too agressive, hills are too steep. The overall impression of land is that it's ginormous, it has to do with scale; all objects are too small. When you look int horizon you feel like in Jupiter or like a bug in the ground.
So in short : Less detail, smoother land, localized noise (stronger by elevation) and bigger objects (trees, vehicles) may save some computing power and improve the looks.
Textures: the textures in the texture packs are not seamless, aggravating the feelling of repetiviness. I see animated shaders for objects like the shuttle and the teleportation devices, it's a bit disturbing, I'd prefer that on the static ocean, and clouds.
Fog: is there any? Hiding geometry with volumetric fog can boost up speed.
Atmosphere: it looks self iluminated; the algorithm for the scatering is it dynamic or precomputed? We get light in absense of light?(I'm talking specialy about the editor).
This game is making great improvements, but I believe that we are in an era were looks, are a bit more important than playability. Make the planets look better, let's add more stuff to the shuttle, ok laser, but also some functionality, like the shield should work on upper atmosphere at a certain speed. At low altitudes you get incandescence only at Mach 5... Maybe build a city or two it might be just blocks, but at least have a location, a place to go on Land.
I'll add more stuff later....
Keep up the good work [I have got a huge grin on my face everytime I play the demo

], Big fan.