Disclaimer: This is IMHO and rankings may change down the road. Also and more importantly, more recent series seem to be trying t0o eschew the "monoculture" trappings that the older series relied on. That, regardless of anything else, deserves some credit. But considering these are hour-long shows and not always with arcs or how they're telling the story, the monoculture and single-species-per-planet aspects were there solely to keep minutiae and excess reality-driven complexity down, but the ambition is appreciated. With that said,
The "gold standard":
1. TOS (which is monumental, for reasons that make their own post... unless anyone needs a quick nap, in which case I can start meandering in Sheldon Mode right now? But being the 1960s, TOS was doing a lot to show a united America, with Klingons and Romulans being placeholders for other societal structures, et al. Yep, it's dated in places and has casual sexism. Considering the time in which it was made, it was having to balance forward-thinking with what censors wanted.)
2. TOS movies, which actually succeeded in going above and beyond the limitations and scope of the original. #s 1 and 2 are more likely going to be rebooted partially because of this but partially because they're still the most widely visible/recognized, even nowadays.
Really good:
3. TNG (The first spinoff to shake up character archetypes in roles and experiences, even the early stuff isn't bad (mostly due to goofy plotting and being the first to find their own way since "Star Trek can't be redone!" being a prevailing mindset of the time.) In some ways, some episodes better TOS (which was not cheap to make, either), but at the same time there is a move toward tighter character drama, which also became "soap opera" later on when the show started to coast. Plus, TOS gravitated toward societal structures on a macro level. TNG-onward started on the inverse, also heading into navel-gazing that forgets that the macro-level is also important too, though to be fair TOS could have started peering toward that belly button too, and I don't mean 60s censorship having to hide it as a literal meaning... Not to mention, Gene Roddenberry himself wanted TNG to replace aspects of TOS/Kirk movies he disliked in crafting his ideas of the future... Sources:
1,
2. Given how some areas of TNG went into and with little smoothing dialogue to make the segue work (even "The Orville" did a better job on one issue... at the end of the day, it's called "sci-fi/fantasy" for various reasons, but TNG held its own and became its own iconic thing as much as it had breached the cultural zeitgeist, something its three direct spinoffs didn't breach (but still had passable ratings).) )
Okay, but with some flaws:
4. DS9 (It's almost two shows, with season 4 being a soft reboot, though the introduction of
Defiant almost qualifies because they had to find new reasons to get off the station for adventure and not just "new possible baddies if not different beings through the wormhole, again" to consider.) Plus, how else would they get to Planet of the Cooties (Risa) for all of those exciting adventures?
5. TAS (Without live action limitations, and a script or two or few lifted from abandoned TOS ideas what with season 4 not being commissioned and all, the makers went all-out and with some ambition. The animation is passable under the circumstances. The acting could be stilted, but voiceover/animation acting is not like live action/theater so it gets an easy pass. But while YMMV, I've rewatched VOY more. But big kudos for the show not wandering into parody territory, which is a hard balance to make. At one point, TAS would be much higher up.)
6. LD (it's a mix of taking itself seriously, with a mix of self-parody, with a mix of comedy. IMHO, it's brilliant because it often juggles all these with ease and having some heart. Plus, most characters have a charm with their archetypes. This is a virtual tie with TAS, depending on mood. But some self-parody does get to be a little much...)
7. PRO (Haven't seen much, but they captured the spirit perfectly. It's hard to place this one as a result, but the tone and feel elevate it a lot, IMH&LO.)
Mixed bag:
8. PIC (Seasons 1 and 2 are mixed but with interesting, if not lopsided ideas, IMHO. Season 3 is why I've placed it this high: It feels like it has newfound focus and verve, keeping the fan-favorite characters of new and pairing them with the classics of old (Raffi + Worf = WIN, IMHO) and moving forward with continuity in ways that generally fit. Yeah, the Borg are brought back but feel more like a proper Borg sequel at the 11th hour when DS9's Dominion are dealt with, even if it'd have been
arguably better to close out the open-ending of "Conspiracy" then plop in the Borg afterward -- and it wouldn't be difficult to fill in newcomers either to that season 1 story. But the Dominion does work as it's the same timeline as the TNG crew, it's just as easy to see why the Borg had precedence and not because "it's a fan favorite", it feels like they were being used to better effect. Plus, and this is big, PIC/3 adds gravitas and reverence to the 90s TNG films, something I thought would be impossible. Kudos, big ones, to that. All that said, some jokes fail to land as they feel antithetical to Worf, but that's a small quibble, smaller if you don't try to think into who the show was being made for (newbies who want the jokiness from the old characters, or established fans who like seeing the same traits but in new situations without becoming fanwanky or detached from the more significant aspects of continuity)...)
9. VOY (I like this one and there are some GREAT episodes - some that only VOY could do, others feeling like they could be done in TOS or TNG ("The 37s" feels like an updated TOS episode for one example of the latter). At the same time, despite the "24th century mannerisms" and "too formal" for dialogue (TNG and DS9 nailed the formula with ease), VOY has episodes that miss the mark, coast too much on rubberstamp technobabble, and franchise fatigue definitely solidifies. But it still has some belters that feel more in-line with VOY than what TNG or others would have to contrive to fit. "Meld" instantly comes to mind, since Suder could be kept in a brig with ease in TNG or DS9 and with no moral dilemmas about execution as penalty for true coldblooded murder for no reason since they're out 70K light years with limited supplies and resources, plus as there'd be no Tuvok, we'd likely see Data getting mindwarped - again - and that would not be compelling.)
10. TNG movies (these never elevated TNG to a higher level than what TOS's had for its progenitor TV series. Indeed, most feel like reunion parties with a shallow plot. GEN holds up the best over the years despite flaws. NEM is too dark and all over the place, but make two surprisingly small tweaks and a flaky movie could have been nigh-on gold standard, except one can't time travel to 2001 to tell them to replace the convoluted clone and Reman subplot and focus it a bit more on a baddie with more nuance to explain (any number of things...)...) INS is a lopsided episode of Jerry Springer. FC is inane fanwank with a big plastic set where they felt that a disappearing viewscreen and easily-breakable plasma conduits were cool plot devices, even more than the pee joke. Yes kids, TNG was doing self-aware comedy long before "Family Guy" had.
Not my cup of tea, albeit not from lack of trying to sit through at least one story:
ENT (prequel + franchise fatigue; "reed alert" was one of the last straws and the Xindi arc was pointless as Earth survives and destroying it would become an alternate timeline - which back then would at least be new but it's easy to see why Earth survives (apart from being gimmicky, but it's been a long while since I watched this spinoff). Trying season 4 again was hit or miss as there is some nostalgiabaiting involved, but Manny Coto should have had a season 5 as he was more than on the right track to revitalize the franchise, when all is said and done.)
DSC (evil Lorca and neo-Mudd were pretty cool... magic roller coaster land for turbolifts and other things, not as much... previous Treks also had high fantasy, but kept it constrained.)
SNW (Mostly for small universe syndrome. Even the big singalong episode was more underwhelming and one small tweak could have fixed it (mind control rays are not often used and that would have been brilliant in that episode...)
Section 31 (looks more like a Star Wars outing.)
SFA (they must have watched certain Voyager episodes and expanded on the academy tales there, but even if the idea of Academy was to be done for ST6, it'd still be a pass. Same reasons as SNW.)
Abrams movies ("Beyond" was pretty solid, "Into Darkness" didn't need Khan whatsoever but was included likely to appeal to some group of fans, and the 2009 outing was just fluff coasting on stereotyped character memes (green women, Doctor line, et al) than characters given any substance, even though we're told outright this is an alternate timeline where things could be different (which that aspect was told fairly well, just not made real use of...)