I loved TNG. I ended up loving the earlier seasons despite being cheesy. For me anyway, cheese is preferable to what seasons 5 - 7 became. I'll take it on story-by-story basis. Picard was like the grade school hall monitor that reminded errant children to walk or to break up fights. Well, he did that as well as being a glorified taxicab driver too.
But DS9 was daring in more ways - it had to walk a fine line between Gene's magical unicorn utopia... and expand it with more interesting things that didn't always mesh with his beliefs. It's not like he explained how humanity got to where it became, or that people would believe it anyway but I digress. So we ended up with more evil admirals than the capacity of a hotel in Los Angeles prior to Coronacooties, a super-dee-duper secret organization (that admittedly was compelling, based on
how it was introduced (but got worn out all the same, so thankfully they brought it in toward the end of the show's run to eke out more plot fodder)), and gray morality areas that just couldn't have been done for Picard. Just think Eddington and an arc whose zenith was "For The Uniform" where, had Kirk or Picard made such an order, the crew would shriek how he's controlled by incorporeal balls of light aliens and promptly ask into thin air where their captain's been taken to and for the 5th time or whatever. That's not the case for Sisko. Sisko had so much respect and by a crew that clearly understood what was going around them that they gave him the benefit of the doubt. Not unlike Riker to evil Admiral Pressman only this time we, the audience, get to see the build-up and know Sisko's been painted into a corner whereas in TNG we're told he was just in the wrong. DS9 was a bit more multifaceted than the series that spawned it.
But DS9 really was the closest Trek got to dealing with actual frontier issues next to TOS. (Also note how DS9 coincidentally picked up new steam after... getting an actual starship for characters to travel around in. The space station had been made great use of, but the same show proved a starship could always go the extra mile. And the Dominion issue led to the authorized use of a cloaking device, which made things even more interesting.) Sisko isn't the hallway monitor Picard was. He's having to blaze trails and take risks Picard would never do. Not without some dreary speech about "muh prime directive" that he, like Kirk, broke on occasion too.
That and DS9 had more elaborate outfits for so many alien species. And more elaborate sets. This show went out of its way to show what can only be described as "conceptually alien". Even if they ended up using control panels on the space station that are just as cheap to make as those on the Enterprise.

The graphic designs alone were top notch.
(You're not bored yet? The best is yet to come!

)
Did I talk about characters? Well, for TNG:
Picard = stuffy taxicab driver Marty Stu
Riker = Kirk wannabe with cool chair-sitting trait

Geordi = nerd who can't get a date but half the time doesn't care about wanting one either
Data = Geordi's best friend
Troi = senses the obvious yet didn't realize she got a raw deal. Has eaten more chocolate than everyone else in the 24th century combined and still looks great. What's her secret!
Beverly = the dopey dancing doctor
Wes = the Marty Stu when Picard isn't
Worf = strong butch guy who gets pummeled every time there's an alien on board
Yar = got a raw deal despite having a background that's not out of place in a horror movie. And, like RIker, had the moves going on too.

Q = tries to put sense into Picard but using atypical means
Guinan = had some dealings with Q but who cares about where any of that hinted setup could have gone, as she was given all the psychobabble stuff Troi would have gotten and then started lighting up a million candles in her cabin despite the automatic fire suppression system
Most of them being placid because humans evolved in 400 years, apart from when they didn't. I'd reckon the actors cast had more to do with keeping the show afloat, there is something about the cast that really gels and Roddenberry and Justman nailed it. Which is a good thing because few of them got any proper development, and even by the 1980s ensemble pieces were very much possible.
As for DS9, and they all got a proper ensemble treatment:
Kira = upfront freedom fighter and bitter
Bashir = hawt naive doctor who hasn't had to live through what Kira had and finds deep space exciting but isn't the most socially acute despite being really cute

Odo = Picard, but with balls
Quark = likes playing with balls since he tests Odo's patience
Dax = has lived a dozen lives and can offer numerous perspectives. Always refuses the direct advances of Bashir. Which is unfortunate because they could have tried one date, he'd realize l that apart from the

he wasn't even remotely compatible on a personality/intellectual level and go wander off back to his monthly IA sessions in Holosuite III. (IA = "Incels Anonymous", donchaknow...

)
O'Brien = married but often acts like Geordi
Keiko = prefers a simpler life
Worf = fits into DS9's gaggle of misfits a lot better than the walking popsicle sticks of TNG.
Sisko = Utterly no nonsense, even outgrowls Worf. He's commander of a space station dealing with a bleepload of situations. The crew respect him as much as he respects them but this isn't the Enterprise thanks to the number of people on station and possible situations that can and do arise.
In short, DS9 has more fleshed out and complex characters. I can relate to Data more than most if not all of DS9's motley crew, but it's the range and interesting backgrounds of these unique characters and how they mesh that make it all work. Not unlike "Blake's 7", which features a gaggle of disparate personalities - but stuck in a different situation entirely.
Unlike TNG, DS9 is serialized - this does require a bit more involvement to sit through, noting that shows like "Police Squad!" got axed after
6 episodes because it was deemed unfair for an audience to have to sit down and actually watch the thing to appreciate it - which amusingly suggests a lot more about your typical bog standard shows in turn. But that's 1981 for ya and serialized shows wouldn't find any real stride until the 2000s... But
Gimme a Break... That was a fun show too, despite their changing the format between every season. The first season was the best, and Joey Lawrence's introduction in season 3 wasn't that great despite my being in the target demographic and why am I nattering such flapdoodle about a sitcom? Because DS9's characters win out in personality differences and were not just well-acted popsicle sticks to appeal to broad, bland demographics. Yep, my ramblings do have some twisty little point somewhere. And don't tell me I need to go out more unless you're willing to help me at the movie theater and restaurant and hotel in Encino after that!
To summarize whatever that little novella was that I just typed up:
TNG may be comfy food like cake and ice cream, but DS9 is the full course 10-course meal, complete with gobs of broccoli and cauliflower that the dumb and stupid children refuse to eat because those don't taste like chocolate and have nutritional value. As well as the ice cream. Now that I think about it I could have summarized first then induce sleep into the reader afterward but it's too late to get a time machine.
And lastly, "popsicles" is recognized by my spellcheck utility as "ossicles". How cool is that, huh?
