The latest dev diary talks about adding "terrain" and how it affects space travel in DW2...
https://www.matrixgames.com/news/distant-worlds-2-dev-diary-4The main takeaways appear to be:
1.) The free/open travel from the first game remains, but nebulae and space "storms" will now generally force (or at least strongly encourage) you to navigate around them.
2.) This, in turn, will often require multiple jumps to reach your destination, especially since...
3.) Your jump range is now generally shorter than your fuel range.
4.) All of these things in combination means that star systems in DW2 can be important for their strategic location.
On another note, I'm really digging the ship models shown in the screenshots. There's no question they've got a bigger art budget this time around.