There are those in Star Trek who make mistakes and those who are never given the chance to show what they are really made of. Whether its a behind-the-scenes reason like the writers being unable to figure out what to do with them or an on-screen reason like an untimely death, some characters simply don't get a satisfying depiction.
There are those who are talked about more than they are seen, which is frustrating as an audience member. Teasing the arrival or the deeds of a person without actually delivering on that is just cruel, something that needs to be addressed in the show. Thankfully, with Discovery, Picard, Lower Decks, Prodigy and Strange New Worlds on the way, there is ample opportunity to rectify almost every single name on this list, saving them from the poor positions that they are currently in.
Then there are those who may simply be lost to time. In those cases, we may have to hope for expanded and extended universes to do their best to offer them the redemption that the show was unable to.
10. The Equinox Crew
The crew that remain on Voyager from the doomed USS Equinox are stripped of all rank at the beginning of Star Trek: Voyager's sixth season. They are then integrated into the main crew, having been informed that they will not be given an easy ride. They'll need to earn the trust of their peers and crewmates, along with privileges. With this stern talking to off Captain Janeway, they leave the conference room and get to work.
They are never seen again.
What are they doing? Did they all survive the next two years in the Delta Quadrant? Did they ever get treatment for the psychological damage left on them during their time aboard the Equinox? They are all members of Starfleet, even if they forgot the main rules of the organisation for a little while.
They did, in essence, follow the commands of their Captain and First Officer. While that doesn't excuse their actions completely, one has to wonder what they would have done, or what would have been done to them, had they resisted. Therefore, checking back in with how this crew got on aboard Voyager is both essential and a large oversight on the show's part. The Autobiography of Kathryn Janeway by Dr Una McCormack addresses this and is a fantastic read.