After a series of questionable decisions, which were part of her rebellious phase, Missy seemed to have finally regained her senses and realized the error of her ways in the Young Sheldon season 6 finale. While on their way home from dropping off Sheldon and Mary at the airport, Missy and George were forced to leave their car and lay flat on the side of the road as the Medford tornado passed. After their near-death experience, Missy suddenly broke down and apologized for acting up. Considering Missy's track record, it was clear that she was only rebelling as a way to get back at her parents for constantly ignoring her.
Missy's tearful apology in the Young Sheldon season 6 finale appeared to be the beginning of her redemption arc. That being said, a CBS marketing video for Young Sheldon that updates fans about the Cooper kids' current situations states that Missy is still "in her rebellious phase." This means that coming into season 7, Mary and George's only daughter will continue to wreak havoc despite previously claiming that she will finally make amends and behave correctly.
While Missy continuing her rebellious phase is bad news for the Coopers, it's a good development for the future of Young Sheldon. The Big Bang Theory canon says that Sheldon's time in Texas is coming to a close, but the rest of the family stays in their home state. Admittedly, Missy's rebellious arc isn't exactly the ideal storyline for the character. It's heartbreaking to see her act up after being the best Cooper for years. That being said, it's so much better than sidelining her again. Continuing her rebellious arc ensures that Missy continues to have an ongoing storyline in Young Sheldon season 7.
Beyond the show's guaranteed run, this plot can also be the springboard for its future. Despite having a titular character, Young Sheldon has become more of an ensemble series, with an increased focus on the rest of the Coopers. This means that it has a good chance to continue even after Sheldon moves out of Texas. Missy could replace her twin as the series' new central character, as it delves into more stereotypical growing pains than the boy genius' unique experiences. Doing so could make the sitcom more universal, as it could entice viewers beyond those who know it from its ties to The Big Bang Theory.
The Big Bang Theory offered an idea of what the future holds for the Cooper kids. While Sheldon excelled as a physicist, eventually winning a Nobel, and Georgie became a successful business owner, Missy spent her time in a miserable marriage with an unfulfilling job. The only Cooper daughter having a worse adult life compared is a disappointment, considering her massive potential in Young Sheldon. Missy may not be a genius like Sheldon or business savvy like Georgie, but she is the most well-rounded Cooper kid. She is emotionally intelligent, no-nonsense, charming funny, and beautiful. She could've done whatever she wanted professionally, and she would've likely succeeded.
Exploring Missy's rebellious arc could offer an explanation for why she never reached her full potential. Although Young Sheldon started as an origins story for Sheldon, the increased attention given to the rest of the Coopers, particularly his siblings, means that it could also function as a prequel for their The Big Bang Theory stories. For the most part, Sheldon and Georgie's childhoods in Texas line up with what become of them in the nerd-centric sitcom. However, Missy's future doesn't make sense, especially if she's going to start her redemption arc in Young Sheldon season 7.
If Missy continues to act up and stray from the straight path in Young Sheldon season 7, there are several benefits to the franchise's storytelling. Firstly, ensures that Missy will not be overlooked in the prequel moving forward, and she will continue to have her personal arc, similar to what Young Sheldon has done with Paige. Secondly, it strengthens The Big Bang Theory canon by offering an acceptable explanation for Missy's less-than-ideal adult life. It's one of the biggest mysteries of the show in connection with Young Sheldon, and the increased interest in her emphasizes the need to also cater to her overall story.
CBS can do this by properly ending Young Sheldon after its titular character moves to Pasadena. This way, it isn't further breaking The Big Bang Theory. However, similar to what ABC did when they spun off Roseanne into The Conners (although having a very different context), CBS can launch an offshoot of Young Sheldon with The Coopers. The ensemble will follow Missy and the rest of the Coopers as they continue life in Texas after Sheldon moves out. Since The Big Bang Theory didn't reveal much about this time in the Coopers' history, CBS has more creative wiggle room to craft its story.