It's just that once Deep Space's Uniforms turned grey it was all about the war, it was a depressing show, and every show it seemed like was about the war. Thats another couple reasons why it was hard to watch toward the end to. The earlier episodes were more accessable to the casual TV watcher or Deep Space viewer.
Every season of DS9, Voyager, Enterprise saw its ratings fall vs. the previous season. The common pattern was a slight bounce up in fall over last spring, down in winter a bit, really down in spring. Except for spike rating episodes (e.g. Way of the Warrior, Scorpion I & II, Trials and Tribble-ations, series finales), nothing noticeably turned this around, not even Worf on DS9 or Seven of Nine. The final season did see DS9's ratings fall far less than Hercules & Xena, which started to fall off a cliff in 98-99 (evidently shows like Seinfeld and yes, even The Nanny were bumping it out of its timeslot. They entered syndication in reruns and the mantra switched from action hours to comedy reruns). It shows people were highly motivated to stay and watch the final season, but except for the finale, it didn't bring back anyone. The Dominion War didn't seem to drive more people away than the usual bleed rate, nor did it attract a bunch of people.
TNG had a rough start too because of its earlier seasons, or so I've heard. I've also heard that it really took off in season 4 and onward. Do you know why, or at least have an idea, this happened for TNG but not DS9 which had a wonderful season 3-6 (imo)? I like all of DS9's seasons, and I think season one of that series is much better than what I've seen (half) of season one of TNG. If it's standing in TNG's shadow, do you think it's just because it came later or might it be something else, like it being more serialized?
Its ratings were always good for syndication. It always beat Baywatch (though Baywatch was only against it from 91-94) and was said to have even beat Sea Hunt, the previous highest-rated syndicated series (I think Highway Patrol was the highest before Sea Hunt). Critically, yes, it was seen as uneven, not finding its footing until Season 3. Ratings IIRC went down a bit in Season 2, but kept going up til Season 6, then went down a little for Season 7. "Best of Both Worlds" seemed to get a lot of chatter. It was seen as a "Who Shot JR?" level cliffhanger, though I was just a kid then, so only know what I've heard from others who talked about online/in print about a few years to years earlier. That capped off a really solid season (there's a stretch in winter-spring 1990 that may be one of the best stretches of episodes in Star Trek history, the part with Yesterday's Enterprise, Sins of the Father, etc).
I think DS9 Season 1 was what drove so many viewers away. Season 1s for DS9, VOY, ENT were always a steep line down as many people tune in, then tune out, some staying for more eps than others, but DS9 Season 1 had many dreadfully dull episodes. The Bajorans came off in a really bad light, the lack of exploration (Season 2's strong point), a subdued Sisko (but still Sisko) compared to later seasons all hurt it. They had this wormhole to the unknown there and they didn't really explore it. "Battle Lines" didn't satisfy, "Vortex" was like testing the waters; only "Captive Pursuit" satisfied people's desire for exploration. People saw episodes like "Progress", "The Storyteller", "Past Prologue", "The Nagus" and just tuned out. I've read many people only tuned back around Seasons 3 or 4, though that doesn't show in the actual ratings (unless the ratings would have fallen more if not for those returners). Season 2 got missed by quite a few because when they tuned back, they saw more Bajorans in the season premiere (even though that story was decent). That was too bad because Season 2 had several excellent episodes ("Whispers", "Shadowplay", "Necessary Evil", "Crossover", "Tribunal", "Paradise"). As dated as TNG Season 1 was (with "Code of Honor" coming out of the 1940s), the series had enough going for it that it certainly wasn't dull (I don't think anyone can watch "Conspiracy" and call it dull. Yikes! The goriest Star Trek episode ever). Basically, Season 1 was too light on exploration, too heavy on the Bajorans. When Bajoran-centric episodes got reduced to like 2 a season and many of their episodes were made into Bajoran/Cardassian episodes, they got a better reception.
And TNG had elements that made it go mainstream, outside of sci-fi fans (years ago, many people [sci-fi fans] mentioned having relatives/friends who were cops, firefighters, etc were weren't sci-fi fans but they loved TNG back during its original run. It surprised them that they were into it). That led to many falsely assuming DS9, VOY, ENT were doing more wrong than they actually were that "so many" tuned out after TNG. TNG was the exception, not the base audience from which to work from. The best DS9, VOY, ENT could of had was trying to get as close to TNG as possible.
Also, in terms of critical acclaim, are you talking about just fans or professional reviewers/critics? From what I've read, Deep Space Nine tends to be the best rated Star Trek show by professional reviewers/critics.
I was talking just in general, the chatter online about it in forums. It seemed to have a very positive reception while TNG had some turn really negative towards it for seeming dated and cliched though some who had grown tired of it by the mid '90s grew to appreciate it again (Spike TV launched reruns of it in Oct 2001 and aired it around primetime for I think almost 2 years). I think Syfy was embarrassed recently by TNG reruns out of primetime beating new SGU eps in primetime. '80s fashions did not age well. Troi seems to be the only real punching bag over time (the therapist). DS9 by contrast didn't use '90s fashions that much (some of the clothing of extras).
Voyager had a downright toxic atmosphere during its run (I hate the people who spewed some of the most hateful, vile stuff I've ever seen written about a tv show and episodes during its run in online reviews and discussions). It's held for years though it finally seems like the radioactive isotopes are starting to breakdown/Hazmat cleaned it up and it's starting to get fairly looked out (that atmosphere seemed to stem from BSG whiners, the people who wanted to show to be like BSG, to be darker than DS9 or any network show at the time, except perhaps Profit, and for whom NOTHING ever made them abate their criticism (not "Year of Hell", not "Equinox", not "Scorpion", not "Night" or "Timeless"), and disappointment.
*Everyone* was disappointed in Voyager, but to some, it ranged from somewhat good to mediocre, but for others, that disappointment festered and produced a toxic bile more copious than I've seen for X-Files Seasons 8-9, EFC Seasons 2-5). I remember that totally destroying trying to read anything online about Voyager during its run beyond basic synopses. And worst of all, these hatemongers absolutely loved the worst episodes of the show; they absolutely loved when Barclay & Troi appeared and took center stage from the VOY cast (they seemed to be the people B&B were appealing to in VOY Season 6-7 and with ENT "These are the Voyages"). I do hope Voyager gets looked at clearly because it's not as bad as many think it is, though it's not great (some individual episodes are really good though), but it was still quality television compared to so much of what was made at the time and a lot since.
Enterprise had people hold out hope in Season 1, but with "Shockwave Part II", the tide turned extremely negative. Season 2 showed people they weren't going to deliver on building the Federation and people realized they were making up the Temporal Cold War as they went along. The Xindi arc got high praise and was considered at the time one of the best blocks of Star Trek episodes ever. Season 4 was all fanservice, though some felt it was ultimately too late or was a little TOS-heavy (too much of a good thing, doesn't try to do something else at times). It had a very toxic atmosphere too, though less than Voyager, but a few individuals seemed to make it their life's mission to piss on every discussion being had about the series, episodes at time. They turned their inner disgust and hatred for the series outward and tried to make sure no one got even an ounce of enjoyment out of the series. They even sabotaged that fundraising drive (basically Kickstarter ahead of its time) for Season 5 with allegations of fraud, which were shown to be incorrect but dried up all donations. That made me wish some people could be banned from the internet for life because nothing good ever came from them online.
Sorry to get long winded, but compare DS9 to that. There's little complaints besides Season 1-2 being dull, Season 3 being a bit uneven, Season 4's Klingon War being a distraction. And of those, the criticism is light. Only Season 1 gets a lot of flack. Worf has gotten some criticism for not really fitting in to the show or adding much to it. It didn't have a toxic atmosphere, it hasn't come to be seen as dated (episodes like Homefront/Paradise Lost have become timely, though TNG had a few go up in the '00s too. Heck, I remember people noticing the attack on the Odyssey in "The Jem 'Hadar" had airs of 9/11 [the angle of approach of the Jem 'Hadar kamikaze ship]). Being ahead of the time in subject matter and some tone/style (e.g. "In the Pale Moonlight", "Wrongs Darker Than...") definately helped it. It may very well hold up for decades like The Twilight Zone has.