Late to the party, here, but find it's still in full swing!
First - Wow. Just Wow. If the gameplay is half as good as the cinematics, we're in for a treat.
From the Developer video and stuff posted on-line, it does appear that Star.Theory have started with a brief of - If we were to develop KSP from scratch, knowing what the community likes/dislikes and what mods are considered essential - what would we come up with? If they deliver on that brief then this will be the game of our dreams - literally. So many of the things that various folk have cried out for in 1.x are right there in the specs. Fantastic!
Personally, I am over the Mun to see that not only are mods to be encouraged, but they intend to expose more of the internals to give modders even more scope.
So - my Christmas list is already updated to include a shiny new GP-equipped PC to play this on.
Picking up some comments from the dev video - and what we see in the cinematic - it seems that this is set in the familiar "Kerbol" planetary system, but with some changes - it may be that the back-story is something like - a rogue planet smashed into the system and caused the Kerbals to use their newly developed space faring abilities to go seek out new worlds to colonise? Let's see. This looks like a great ride!
[Edit - actually, maybe the scenario isn't quite what I inferred from views of what appeared to be Duna lit from the pole - hence not in its usual orbital inclination - and the new exoplanets Rask and Rusk that looked as if they'd had a bit of an argument]