DS9 was a different kind of Star Trek
Star Trek: Deep Space Nine (DS9) was a different kind of Star Trek. It didn’t have the same feel as The Next Generation. Things aboard the space station were darker, and there was a lot of inner conflict that Gene Roddenberry disliked. On top of that, there was a differing of opinions when it came to whether or not Roddenberry would have accepted the series.
Rick Berman was quoted in The Fifty-Year Mission—The Next 25 Years—From the Next Generation to J.J. Abrams by Mark A. Altman and Edward Gross as saying that he’d gone to Roddenberry and said they were thinking about a spin-off to which Roddenberry said “great,” and that they would discuss more about it another time. That never happened because Roddenberry wasn’t well and got worse from that point forward.
Susan Sackett said Gene Roddenberry hated DS9
Susan Sackett was Roddenberry’s personal assistant for seventeen years until his death in 1991. According to her quote In The Fifty-Year Mission, Roddenberry had not approved of the series as he hated it, and he did not want it to be done. She said just a week after Roddenberry’s death “they took it and ran with it, and that’s not something I was happy about.”
Sackett went on to say that when Roddenberry was alive he said “you can’t do it. I don’t approve of it.” But her statements has been denied by Rick Berman as he said that he and Michael Piller had pitched their ideas of DS9 to [Roddenberry], and “said it was really interesting, and he’d love to know more.”
Of course, there are two sides to every coin, and we’ll never know what Gene Roddenberry actually thought about Star Trek set on a space station. Maybe he would have liked it. I know millions of fans did, and that might have been enough for him even if he never got around to actually liking it.