So I thought of something just now.. I think the way the romance line for panam ends in both the sun and star help to create a singular path for expansions when she shows up again:
-sun ending, you guys break up with her either hinting that she's down to get back together in the future or not
-star ending, she is having trouble juggling quality time with you and being a chief at the same time
for both endings, even though the star one is clearly better outcome than the sun one because you guys are still together, both endings introduce some obstacle between you. For sun, it's V pulling away from her. For star, it's her responsibilities pulling her away from you.
I think this sets up future expansions to allow for the relationship to be reignited over the events of that expansion in a way that keeps things interesting, versus having everything be happy and perfect. I don't mean it in the sense that panam and v either getting back together (sun) or having their relationship come back from the brink and grow stronger (star) would be the main point of the expansion, but instead it could be a side thing that occurs next to whatever the main event of the expansion is, much like how panam's story line is a side mission in the base game. What do you guys think?