Star Trek episode. The formula is made up of four parts: stories that involve action and adventure, stories that are main character-focused, stories that make social commentary, and stories that are essentially believable.
Star Trek: Discovery has two out of the four elements from the formula, namely the action and adventure and character-focused stories. Seasons 1-3 of Discovery are action-packed, featuring a wide range of stories from the Klingon War to the crew's time jump to the 32nd century. Additionally, Discovery's focus on their main cast has created a show that features a multitude of compelling characters and relationships, and this character-driven storytelling has drawn fans in from the beginning.
Where Star Trek: Discovery falls short, however, is in stories with social commentary and believability. Classic Star Trek, especially shows like The Original Series and The Next Generation, had a reputation for using their platform to hold up a mirror to society. Most episodes of both TOS and TNG were little morality plays, in which a social issue such as race, class, gender identity, sexuality, etc. was explored. While some themes in Discovery season 3 did allude to the current moment, and the show has explored issues of sexuality and gender through their inclusion of LGBTQ+ characters, the idea of a morality play seems to be a thing of the past. Star Trek: Discovery is not a vessel for social commentary in the same way it could be argued The Original Series was.
Arguably, however, Star Trek: Discovery's biggest issue is with believability. Roddenberry's formula stressed that, technology aside, if the audience would not believe a storyline if it were happening today, then they won't believe it could be happening in the show. In Roddenberry's opinion, the essential plot of a Star Trek episode needed to be a story that could happen in any time period, and Discovery's storylines sometimes fall into the trap of things happening for the sake of driving the plot along rather than because of a clear character choice or motivation. Roddenberry also had a relatively strict definition of science fiction which Discovery has stretched. Roddenberry's definition of science fiction was that the explanation for technological advancements should come from "generally accepted" scientific theory. Some of Discovery's technology, especially in season 3, push the boundaries of this idea that science fiction should be rooted in actual science. While the spore drive, for example, is rooted in some scientific fact, the way it's utilized in the show is a giant leap from the accepted real-world science.
The Star Trek franchise hasn't always followed Gene Roddenberry's storytelling formula perfectly, but many aspects of it are vital for creating something that fans see as quintessentially Star Trek. While it may be too late for Star Trek: Discovery to walk back some of the potentially scientifically-questionable technology, the show could certainly attempt to follow the formula more closely by incorporating more social commentary into seasons. In fact, the set up for Discovery season 4 in the season 3 finale may allow Star Trek: Discovery to return to a more episodic storytelling format, something that could facilitate bringing back the idea of the classic Star Trek morality play.