Ever since Star Trek first hit the small screen in the 1960s, there have been a plethora of new and exciting iterations into the franchise. Some of these have been more successful than others. For example, the The Original Series has been highly regarded by some, mostly fans who watched it when it was released, but also slated by others for having some pretty wacky plots, and some uncomfortable moments, despite its aim to be diversely groundbreaking. The Next Generation is another that had a large fan base, while programs such Deep Space 9 often divides people, some really enjoying it for it’s grittier look at the problems of the Federation in a time of war, others unable to properly enjoy a standstill story focused on politics.
It is Voyager however, where a lot of fans stand together. Many aren't fond of the program thanks to its boring story telling, dull characters, and mostly nonsensical plot. The first few seasons were the most turbulent, and at the center of it all was poor Kes.
Kes was an Ocampa, a race of humanoid beings native to the Delta quadrant, where the USS Voyager was whisked away to by the nefarious caretaker's array. The Ocampans are a race of short-lived beings, with a life expectancy of around eight or nine years. As a result of their quick aging, they develop very quickly, being able to learn and process information at a high level all within the first 6 months. By one year of age, they are considered to be adults. Ocampans are also considered natural telepaths, being able to communicate mentally with their own race and the races of others. In the Star Trek universe, telepathy is something that all beings are capable of; some are not born natural gift and others are, like the Betazoids and Vulcans. The Ocampans were also known to harness their ability to see into the future, and present various telekinetic powers.
Kes joins the potential war criminal Captain Katheryn Janeway’s ship right at the start of the series, and became a valued member of the crew. She sticks around for the entire first season, until the episode “The Gift” during season 2. Throughout the story, she becomes more and more in touch with her telepathic abilities, harnessing them in various different ways until she began to give off massive power surges, and her mental powers began to overwhelm her. This is when her telekinetic abilities started coming through more prominently. She manages to use these to perform complex surgery alongside the holographic doctor, using just her mind.
This was great for a short time for this newly almighty character, until she began to destabilize, falling apart at a subatomic level. She started to rip the ship apart, putting it in a constant state of red alert. To save the ship, Kes took a shuttle craft and left, wanting to explore her new powers without hurting anyone. It is heavily suggested that she transcended the corporeal world and became pure energy, similar to the Q in many aspects, but the specifics are left ambiguous.
This is what happened in-universe to Kes, but it’s interesting to explore why this happened. The main crew during Voyager mainly stayed the same, only adding the occasional member to the rotation such as the ex-borg Seven of Nine. Kes was the only one to leave the crew and thus the show, and it all happened rather quickly, only four episodes into the second season. The biggest reason is that the character never really caught on with audiences, being regarded as poorly written and fairly boring. Her character was interesting, and offered a unique lens to look at a whole new way of life from a species that aged so rapidly. However, this all fell flat for fans, as a result of a mixture of what they often refer to as convoluted plot points and poor acting.
The problem with Kes, however was much bigger, her lackluster response being the perfect mirror for review of the show. Voyager was never a fan favorite, but this went two-fold at the start. When it came to Season 2, the writers knew they needed to shake things up a bit. It was a dull meandering voyage, which in some ways is perfect as that sums up exactly what the show was about: a 78-year slog to get home.
Kes’s departure was timed perfectly with the addition of another, the stunningly memorable Seven of Nine (played by Jeri Ryan), a character that has become as iconic as many of the other shows' protagonists. The producers knew they wanted Ryan in the show, and they also wanted to cut an existing character to make room for her. Apparently Gerrett Wang, who played ensign Harry Kim, was at the top of the list of people to go, but they decided to keep him as they thought replacing the show's only Asian character with yet another white actor would not go down too well.
Kes was one of those characters that starts out with a show, but was unable to keep up with the speed and direction the show needed to take. She became more and more extraneous, fading into the background compared to the others and their personal story arcs. This was made all the more apparent in the few episodes she appeared alongside Seven of Nine, the shiny new addition to the show that became an instant success. It’s also rumored that actress Jennifer Lien was unhappy on the show, and may have even been the one to suggest departing, but this is unclear. The decision to replace her with Jeri Ryan was the best choice the writers could have made, with Seven on Nine practically carrying the entire show all the way through the seven remaining seasons.