If I were to rate the seasons best to worst...
Season 1 > R / S > Stars > SuperS
I like every season, but the Amazon Trio arc was very badly paced with a lot of bleh episodic episodes, and only got good at the last minute (and in some ways it was too late by then, they really should've been setting up that concept more in advance and fleshed out it's implications better and given the Trio more time to change what they were doing based on the impending doom and so on). That arc still had a lot of good little moments, but overall it was the worst.
The rest of SuperS was also a little off-balance, and the whole season had a problem developing Helios/Pegasus' character in any likeable or interesting way, always defaulting to making him frustratingly, insultingly, disrespectfully secretive, always demanding assistance and trust from others without explaining anything or trusting them in return, and
never getting called on it or suffering any consequences for his jerkish, mistrustful behavior, that little twerp.
So SuperS is definitely the least good in my book. But I like Fish Eye, I like the Amazoness Quartet, I like "Zirconia's" reappearance in the finale
(as a freaky chestburster!), I like the
idea of a girl romancing a sapient horse, I like the golden crystal/Elysion bit but desperately wish they'd said more or, though they'd never do something like this, referenced the Shitennou even briefly... I liked the Trio's last two episodes, I would've liked to see them again after that one (even though I was sick of them beforehand), and I would've liked to see the Quartet in Sailor Stars. Alas. Also, Diana's introduction was great and Minako double-dating Tiger's Eye and Hawk Eye was great. And Naru shoving Tiger's Eye off the bench was great, and then torturing Umino with milkshakes.
It's 'least good', not 'terrible'.
I outright love my "second worst", Stars. The problem is that it had it's own (shorter) dawdling not-very-story-advancing part with most of Iron Mouse's arc when it was the shortest season, so when it got to it's cooler ideas it kinda zoomed past them. At the same time, it didn't answer some of it's own questions very well. I think the whole Shadow Galactica arc could've stood to be a bit longer (or been heavier-paced, maybe like season 1's Zoisite Arc where something always seemed to clearly be developing and building up), basically.
Essentially, the last two seasons would've been like 80 times better if they didn't introduce any (or very few) new one-off rando characters and stuck to developing mains and recurring characters, and kept bringing back older recurring characters instead of pulling out new ones no one gives a ascii-sad-face about. ESPECIALLY SuperS.
Characters like the Animamates or the Amazon Trio are great additions, but not random concert conductor victim guy or the little girl who wants to be the best swordswoman or Makoto's old friend who's a writer
who could just as easily have been Kinozuki making a reapparance or any of those boring, awful randos EVERYWHERE eating up screen time in return for shallow, unsatisfying dawdling while I'm eagerly waiting for someone important to get back on screen. I don't even hate any of these individual characters- I kinda like Kamoi for example- but there's just way too many of them and it wastes time that could be (and otherwise often
was) spent on deeper storytelling.
Anyway, there's also things that could've been better about R and S, like the "Witches 2" issue, Kaolinite's weird anticlimax, Rubeus kinda being bleh, Saphir's screentime being too short, undevelopment of the Ayakashi sisters, and so on. I think the Makaiju arc was fantastic as-is though.
Season 1 had no real failures in my eyes, only missed potential to be even more awesome, like if the already-excellent Episode 44 had been some big multi-parter about how Endymion's kingdom fell, or something like that.
Almost every season makes me mad by introducing logic that suggests the sympathetic side villains might or might not be dead afterwards and then doesn't explain it:
- In season 1, the year seems to restart and the major damage from the disasters at the end of the year seemed to be undone. Where does this leave the Shitennou? Jadeite didn't even seem to be properly dead before the reset.
- In R, the future gets rewritten so that Crystal Tokyo is apparently not invaded (they show it all pristine when Chibi-usa comes back). So are the Black Moon Clan still dead? What about the Ayakashi sisters?
- In SuperS, Pegasus tells the Amazon Trio to wait in Elysion until the dark crystal forest becomes light again. The trio is never seen again, and the crystal forest and Pegasus aren't seen after the ending, which Nehellenia survives and returns from. Mamoru had his star seed taken... does that affect the golden crystal, assuming it's even related to his golden star seed? The Quartet outright talks about how they may meet again in the future in their final appearance. What happened to any of these plot points??
- In Sailor Stars, Galaxia goes to try to return all the star seeds, though she expresses doubt about her ability to undo all the damage. We see her return the ones she took from Earth- but what about the Animamates? They're probably gonna be okay, riiiight? The show's sure as heck not gonna tell you, though.
Also:
- What's up with the scene where Sailor Pluto takes baby Hotaru? Where is Professor Tomoe after that? Did he agree to any of this? Why isn't he with them in the finale or anything, ever? What's going on?? At least one forum member around here seemed to basically assume Pluto just whacked him on the head with the garnet rod and ran off with the baby, because there's absolutely nothing to rule that out.
- Speaking of which, why do all four outers seem to have a spooky, kinda-evil vibe...?
- The entire show leaves the cause of the pre-Crystal Tokyo "cold sleep" of the entire Earth completely hanging, never to be explained.
But they're all still good enough to make me CARE about all those loose ends, so they were doing something right. This stuff is a big part of why I've been working on fanfic.
I love this show, but I'm not gonna be like "oh it's perfect". I'd rather have a billion boring randos than
too little character development and the story moving too quickly and abstractly to really be able to grow, which is the problem I feel in the manga instead.
But it'd be nice if they could all be paced as well as Zoisite's arc (or about episode 23 through 35). Those were the days. The Rainbow Crystal randos were all pretty good (especially Ryo), and the one that wasn't developed very well stayed out of the way for other, better-developed characters (Naru and Umino) to take the spotlight. And then Ryo returns in a later episode! There was the sense that these characters might ever matter again, which was lacking in later days. Likewise, the ongoing "who's got how many rainbow crystals" tally was much more interesting than "does
this rando have The Thing? Nope, of course not, a main character has The Thing, but we're saving them for last even though it's so stupidly obvious."
More generally, the bigger your main/recurring cast, the less time you have for randos. S, SuperS and Stars' answer to this was to sideline/discard fantastic recurring cast members in order to keep fitting randos... which is a really bleh writing move, and pretty much the worst thing about the show. A much better approach would be to reuse randos for new developments, or spend the time developing recurring cast better instead of having so many episodic episodes in the final seasons to begin with.
But good writing is hard (my own biggest weakness, I think, is using too many words and oversdescribing, and sometimes I run out of new ideas), and when this show is firing on all it's cylinders, it is
amazing. I don't regret watching any of these seasons.