If the show stopped at season 6 I would agree. But season 7 might have single handedly destroyed the show and made it right there with Voyager. There's just so many flaws with that single season. It might be the worst in all of Star Trek history.
I've never understood nor agreed with this viewpoint. Season 7 may have had a few bad ideas, but nothing so bad that I'd want to stop watching after season 6, or say that it's worse than TNG's first two seasons, or Voyager's second season, for example.
I can go down the list if you want. There's really not that much to like about the 7th season.
Lets start from the beginning. The first episodes you have a lot of things that are disturbing.
Basically you find out Sisko is half profit then he gets stabbed for no apparent reason and IT WAS NEVER EXPLAINED! If a main character gets explained don't you investigate why? Then after being stabbed suddenly Sisko recovers immediately then goes on a mission then suddenly some child like character comes in and says she's Dax.
You replace a Dax with a weaker child basically to play that role. A role with 10 life times basically becomes a whiney little child like character. Look at Ezri she complains nearly all the time. I came from kinda liking Dax before to hating Dax just like that. When Jadzia was Dax I remember some people complaining that she wasn't a strong enough character. I kinda disagree but I can understand that a little bit. But you replace her with a character that weak.
The Bajorans who had no idea that there was a wormhole 5 years before and were faith based, most of their people didn't need orb of anything to have their faith. You don't see someone go from being a christian then for some reason losing all faith then praise Satan for almost no real reason. Yet that's exactly what a portion of the Bajorans do. They suddenly start praising Hell.
Was having a holographic bar really necessary when you have Quarks? I understand having a similar thing in Voyager. It actually fits in that show a little better. But we already have a bar where everyone hangs out in Quarks on DS9. Why have the entire Vic Fontane thing? Yeah Quark doesn't sing but he's pretty much better at everything else than Vic is. There was no need for this entire thing on the show. And I don't see Quark allowing for something like that also because it would be bad for his business to have another bar. Really the only reason to have it was someone singing a couple 50s Sinatra type songs and I have great respect for Sinatra. It just doesn't make sense for a SciFi show.
After basically dominating the war for most of 2 years the Dominion suddenly become dumb. Yes the Federation did start to fight back and gain some ground in season 6. Won back the station but still things weren't going great for the Federation. Then come the Breen. How do you create a character that everyone understands what they say except the viewer. Do they really think the viewer is that stupid? The only reason to add that type of character is to laugh at it because it's a stupid character. And it's not like the Breen were ever really thought of as a big deal in the history of Star Trek. They were always a back ground type character in TNG. Suddenly they have a weapon that the Federation can't beat? Where did this come from?
The other part of the Dominion being dumbed down is that they were basically beat by group of Cardasians and Kira led by an alcoholic back ground character for most of the show. I still don't understand how they tried to make Damar a leader. I didn't see him as a leader at any point. He's Dukat's 2nd in command then he's the 2nd command to the Dominion and an alcoholic. Even when he becomes an underground leader the only reason they show him as a leader is because he says he is. He never actually does anything as a leader. Somehow that group beats the unbeatable dominion. Granted he dies at the end but even that was emotionless.
Now the worst thing of DS9 or any Star Trek ever. The entire Dukat/Winn thing. All of it is awful. It starts with Dukat in season 6 coming from nowhere senselessly kills Dax with fire power from the Pah-Rates, closes wormhole which hurts his side in the war does no real bad for the Federation at all. Darkens the orbs and somehow the Bajorans start losing their faith. Again read above on the Bajoran thing. But he laughably disguises himself as a Bajoran. How the hell was he not caught? I laughed when I first saw him walk on as a Bajoran. Somehow Winn buys it and when she finds outs she converts to Satanism anyway.
Winn and Dukat in the first 6 seasons were always bad but you could understand their motives in someways. Winn was just misguided in her faith. Dukat just wanted what was best for him and his people. Now they both basically become Satanists and this really comes out of nowhere except for Dukat being completely insane because his daughter was killed by the same guy that somehow leads a rebellion on Cardasia against the Dominion.
Now to the end. First off I still don't get the Bashir/Dax thing. I mean WHY? That really served no purpose except to put 2 characters together. Just like 7 and Chackotay getting together the last episode. I still don't get it. But you have Odo leaving to heal his people who are evil and just tried to take over the Alpha quadrant and have been the same way for thousands of years. Yet he expects to change that attitude. Yeah right! Sisko leaves to save Bajor from Satan(Dukat) in the Fire caves in a real weak fight. and leaves his wife and baby alone. Worf leaves for basically no reason. Miles leaves also. Why does everyone have to leave in the last show? That basically destroys any chance for a future TV movie or mini series or anything like any fans want. I can understand having Sisko go to Profit heaven to be with the profits but why does everyone leave?
I can really go on and on about season 7. It's all around awful. This is just the tip of the iceberg.