Roddenberry didn’t want Worf to have a big role
The Klingons were written as enemies of the Federation, specifically for Captain Kirk and the crew of the Enterprise in Star Trek: The Original Series. They were never meant to be heroes or the main focus of a Star Trek television series, especially not one led by Captain Jean-Luc Picard. Gene Roddenberry believed that as Patrick Stewart was the lead of the show, any major moment should be about him. But that’s not what happened for Star Trek: The Next Generation’s 100th episode.
Redemption, Part 1 aired as the series’ fourth season finale and the introduction to an in-depth storyline that sees Lt. Commander Worf having to choose between Starfleet and his people when a civil war that could rip the Klingon Empire to shreds looms. Writer Ronald D. Moore, who is responsible for the Klingon world-building that began in Sins of the Father, told Hollywood Reporter that it was a fight to get Redemption approved.
"“I remember that Gene was not fully on board with the idea. He didn’t really see Worf as a primary character. [TNG] was about Picard. He was the Captain. This was the first time that Next Gen — that Star Trek, really — had ever done a big war story like this. And this was going to be the series’ 100th episode on top of it. So, we had to fight somewhat to get the episode going.”"
Worf turned out to be one of the series main characters
Because he was a different species, Worf’s background had to be built within the series. It wasn’t as easy as saying he was born in Minnesota and lived there all of his life. No one knew much about the Klingon home world prior to TNG, and it’s thanks to Ron Moore that Worf did become one of the main characters of the series.
By exploring the Klingon houses and revealing the struggles that took place within the chambers of the High Council, Moore created a dynamic that made Worf interesting, that made his ancestry compelling.
"“At that point in the series, we were at a place where we could really mess with it. Give them a civil war, and let’s really get into how the power struggles with leadership would really work. And explore the great Klingon [family] houses, and the great dynasties and histories. Especially the rules of the planet and how they conduct warfare. I loved writing that two-parter. It was just really fun to go off into that world.”"
Thankfully, according to Moore, Rick Berman and the late TNG showrunner, Michael Piller, intervened and was able to get the two-part episode greenlit for production. And, as it turns out, Worf not only took on a primary position aboard the Enterprise, but he followed that up with a four-year stint on Deep Space Nine.