The original plan for Leia Forman in That '90s Show would have been a terrible decision and could have ruined Eric Forman's character development from That '70s Show. Initially, the plan for the sequel series was to include Eric having a surprise child resulting from a hook-up with someone at a music festival. The idea never came to fruition, however, due to Netflix feeling audiences wouldn't be invested in that story. Ultimately, the right choice was made by canning the original premise.
Leia being the result of a hook-up was a bad decision for multiple reasons, including dampening the legacy of Eric's relationship with Donna Pinciotti. Additionally, it would've felt out of character for Eric to hook up with and conceive a child with someone who wasn't Donna, as that relationship was the heart of That '70s Show. This storyline was essentially done anyway when a girl became pregnant by Michael Kelso at a concert in That '70s Show season 6. There was no logistical reason to rehash that story, so having Eric and Donna married with a child is a perfect culmination of their relationship from the original series.
Why That '90s Show Being About Eric & Donna's Daughter Is Perfect
That '90s Show centering around Eric and Donna's daughter, Leia, was the best decision the series could have made. With the revival taking place over 15 years later, it can now continue building on That '70s Show's finale. Since Kelso and Jackie end up married in the new batch of episodes, it's cathartic that Eric and Donna got that same luxury and began a family shortly afterward. The sequel series is meant to revolve around the next generation of teenagers hanging out in a basement, and centering on Leia is a nod to Eric being the central character of That '70s Show.
Because viewers are being introduced to newer young characters, time can now be spent on developing their arcs instead of focusing on the show bringing the legacy cast members back and revolving around them instead. Leia being the main character among her friends works perfectly because it continues That '70s Show's legacy by including an offspring of two of its main characters and creating the story around that. Eric's parents, Red and Kitty, are also main characters in the sequel series, so the family legacy can also continue.
What We Know About Leia, Eric & Donna's Daughter
Serving as the main protagonist, That '90s Show's Leia Forman (played by Callie Haverda) spends the summer of 1995 with her grandparents Red and Kitty (Kurtwood Smith and Debra Jo Rupp, reprising their roles) in Point Place. Like her father, she has a sarcastic side to her personality, and she appears to have inherited her mother's smarts. She seeks "adventure in her life" and friends who aren't members of her family. Her new group of friends will repeat what the That '70s Show characters did and hang out in the Forman basement, perfectly referencing the former cast and reinventing classic tropes from that sitcom.