An integral The Big Bang Theory character, who essentially solved one of the show's biggest problems, almost didn't happen. Despite the popularity of Jim Parsons' Sheldon, the CBS comedy was still technically an ensemble series. After co-creators Chuck Lorre and Bill Prady were asked to rework the original The Big Bang Theory pilot, only Sheldon and Johnny Galecki's Leonard were brought into the revitalized sitcom. Meanwhile, Kaley Cuoco's Penny, Simon Helberg's Howard, and Kunal Nayyar's Raj were added, eventually becoming the foundation of The Big Bang Theory 's 12 successful seasons.
With a solid ensemble cast, The Big Bang Theory was able to slowly grow its fan base. Despite an interesting premise, following a group of geniuses who were also social outcasts, the CBS sitcom wasn't an immediate hit. In fact, the Writers Guild Strike of 2007 indirectly helped in establishing the show as one of the most promising comedies of that era. For several years, The Big Bang Theory split its storytelling into its five main characters, but the show eventually expanded its cast. Whether that was by introducing recurring guests or bringing in new regulars. One of its most important characters, however, almost didn't happen.
Four years after The Big Bang Theory finale, Rauch revealed that her character, Bernadette, was only meant to be a guest role in the show. Introduced as one of Penny's co-workers at The Cheesecake Factory in season 3, she appeared several times, giving her the time to interact with the rest of the main cast when Sheldon and the rest of the boys would visit the restaurant. Between her great dynamic with Penny and her chemistry with the rest of the cast, CBS saw potential in Rauch's Bernadette that she was promoted to be a series regular in The Big Bang Theory season 4.
Since then, Bernadette appeared in all years of the nerd-centric sitcom until it wrapped up its run in 2019. Admittedly, there wasn't much fanfare surrounding the character compared to the original cast and even to her fellow late-comer, Mayim Bialik's Amy. That being said, Bernadette was actually one of the most important character additions to The Big Bang Theory because of what her arrival meant to the show's storytelling.
Oftentimes Bernadette gets overlooked as a The Big Bang Theory character. She was barely at the center of any plot line and was usually utilized as a side character than a main player. Her arcs were almost always tied to her relationship with Howard. That being said, that wasn't exactly a bad thing, especially with regard to how she impacted the show. Before Bernadette's introduction, Howard was sleazy. While Sheldon was downright rude and misogynistic, he was a pervert who unabashedly hit on women. That all changed when he fell in love with Bernadette.
Looking back at it, even Simon Helberg has admitted that Howard was problematic during the early years of The Big Bang Theory. For a show that already has a tainted legacy, mired by criticisms about its brand of comedy, it's safe to say that it would have been more scrutinized if it wasn't able to course-correct with Howard. Whether it was intentional, Bernadette's arrival gave The Big Bang Theory the opportunity to subtly fix its most controversial character. Their romance was very traditional: they fell in love, got married, and had kids. Howard essentially stopped trying to be a playboy when he met Bernadette.
The arrival of Bernadette had an immense impact on Howard and his future. Thanks to her, he was able to have the family that he always longed for. It's difficult to imagine how life would have turned out for Howard had he not met his wife. However, there were other things in The Big Bang Theory that would have significantly changed if CBS stuck to its plan of only bringing Rauch as a guest star on the show.
For starters, Penny wouldn't have been a successful pharmaceutical representative because Bernadette wouldn't have been there to introduce her to a whole new industry after she gave up on acting. Secondly, perhaps Raj wouldn't have felt so alone because Howard would have had more time to hang out with him. Perhaps, they may have even ended up together, considering The Big Bang Theory's countless implications that they had romantic feelings for each other.