I like DS9 very much. It has its faults, but on the whole it is far more watchable than either TNG or VOY. I would submit that ENT is the best Trek, IMHO, but DS9 is a very close second.
I’ll echo many posts on here that emphasize just how awful some of Roddenberry’s ideas were. The first few seasons of TNG are almost unwatchable, and Roddenberry’s incompetence as a storyteller created a lot of problems behind the scenes. I’m not going to say I’m glad he died, because I’m not, but the fact of the matter is that the show improved after he was no longer in a position to dictate what happened on it.
I also reject the idea that Star Trek must be about exploring new planets. That was the premise of the last two shows, and DS9 had to offer the audience something different. Otherwise, why bother making a new spin-off? And the DS9 crew did explore plenty of new places.
But more importantly, science fiction is about exploring the human condition. The trope of travelling to strange new worlds is really just an opportunity to look at ourselves in a new light. The problems that Kirk and Picard encountered were, most often, just variations on the conflicts that we experience in our own world. Most of the aliens they encountered were thinly veiled stand-ins for various people or groups in our own world (cite: “Let That Be Your Last Battlefield (TOS),” “The Outcast (TNG)”). In learning about these people and exploring their problems, they explored issues common to all humanity and we learned about ourselves.
If anything, DS9 had this in spades. The characters repeatedly explored crises and experiences that can be found in any wartime setting. I remember watching it in Kosovo and being amazed at how closely DS9’s plot duplicated that conflict, even though the show was made before the Kosovo War. It was able to do that because the issues it grappled with were so fundamental and common to the human experience.
The scripts, plots, and characters were superior to those of TOS, TNG, and VOY. The fact that the space station was stationary meant that they couldn’t forget about their problems. If Picard pissed somebody off, it didn’t matter because he would be on the other side of the galaxy next week. The serialized stories in DS9 made it much stronger and more meaningful because they had lasting consequences. This is another thing Roddenberry refused to permit, and in this he missed the boat, because serialized stories proved superior and now we are in a golden age of serialized storytelling.
And there’s one more thing OP said that really struck me:
I find this an odd thing to say. I’ll admit that DS9’s first few episodes do give the impression that Bajor is a lonely backwater at the ass end of the universe. This was done specifically to distance the show from TNG, where the Enterprise is a glamorous flagship and everyone on it is the best at everything. But as the plot evolved, it rapidly became clear that DS9 was the linchpin of a galactic conflict. By the end of the series, DS9 was the most strategic point in the entire Federation. The people of the future should be thankful that they had someone as capable as Sisko in charge of her!