Star Trek: 10 Worlds We Should Probably Check On
10. Cardassia Prime
As Admiral Wong put it, "Nobody wants to go to Cardassia Prime. The Cardassians are creeping everyone out." It's true that the levity of Star Trek: Lower Decks might take the Cerritos off the cards when it comes to sombre and solemn missions, like keeping up with the Cardassians. That said, since the end of Star Trek: Deep Space Nine, no one else (on-screen at least) has had the stomach to go back there either.
In 2375, as the Dominion War was coming to a close, Cardassia Prime was reduced to rubble. Over 800 million of its citizens were killed as a genocidal afterthought of the chief changeling with whom Cardassian leaders had made a Faustian pact to conquer the Alpha Quadrant. We can be fairly sure that the Federation didn't just leave Cardassia alone to get on with things, but it would be good to see confirmation of that in canon.
"Requiem for a Hug," anyone?
In our article '10 Story-arcs Star Trek: Legacy Should Continue,' one of the most enticing themes for a 'New Cardassia' in the beta canon is that Garak is now in charge. Just to see the former (tinker-)tailor-(soldier)spy's face pop up on the viewscreen would be worth the trip.