The only thing they showed as a quest there was collecting bear asses from generic dialog with a scientist (but possibly there's more to it) so that's not a great sign. I can live with bugginess but if the content isn't compelling why am I playing? if the content is compelling enough I'll deal with a lot of bugs.
and yeah I think there might be a lot of cool mods around adding content to spawn on these planets if the structure of the game allows it. It would allow modders to create smaller self contained one shots basically without worrying about how it all fits into the rest of the game world.
Basically, preordering incentivizes companies to release games that are not finished.
In general, companies will always maximize revenues while minimizing costs. If they can release a game that didn't cost them as much to produce (getting massive preorders through good marketing but pinching development and quality) then they absolutely will. look at any AAA released this year