Gee, ranking episodes/seasons for me making things seemingly black and white, as nothing is perfect:
I better do the alternative, I just can’t compare the seasons
Season 1 :
Pros: introductory, relatively simple, looney tune slapsticks, lessons made the show, meme spawning pharses, Pinkie and Rainbow Dash were a lot more likable in early seasons here
Cons: few characters/locations (well the show was young then), no 2 parter finale, Rarity wasn’t popular back then
Season 2 :
Pros: 2 parters for both in and out for the first time, both 2 parters are epic, more lessons, CMCs are the best here
Cons: some characters act wild beyond their usual characters (esp. Fluttershy, Twi, Spike but only one episode each), Spike being too much self absorbed in this season
Season 3 :
Pros: Discord being reformed in a clever way, Spike defeats Sombra, short season might be good for some viewers
Cons: Sombra was quite a bland 2 parter villain, no 2 parter ending, short season might be bad for some viewers, Twilicorn was controversial
Season 4 :
Pros: Episodes are getting darker and more complicated, 6 keys made continuity nods, Tirek moment, Twilight’s alicorn struggle shows realism about status ascending ain’t simple, Awesome new characters like Coco Pommel or Maud or Cheese Sandwich, Discord’s moments are entertaining to me
Cons: Pony Flash appeared (at least ONLY in this season), Daring Do’s episode may be entertaining but it sparks problem when in Season 9
Season 5 :
Pros: Starlight Glimmer’s debut as the real-life-esque villain dictator, the use of cutie mark calls making lessons are now focusing on choosing the right ponies for the right problems, more new characters, Diamond Tiara’s and Gilda’s reformation are decent, Rarity is becoming more popular
Cons: Starlight’s redemption was a little rushed that became controversial (but it is fine to me), also shame that this is the last season to hear Diamond Tiara or Silver Spoon or even Gilda talks and having important role despite being reformed
Season 6 :
Pros: Thorax breaks the negative stigma against changelings (also Spike’s good episode), the finale change the pace of who are the protagonists, Starlight and Trixie befriends, nice to see a nurturing stallion Sunburst, Ember’s introduction episode has quite a message
Cons: getting a lots of filler episodes, Starlight uses mind control in one episode made some people still question her morality here, Flurry Heart born as an alicorn was a little controversial, Changelings’ color change has mixed reception
Season 7 :
Pros: Pillars of Equestria’s continuity nod as legends before the 2 parter finale reveal, Fluttershy is clearly being more healthily assertive as character improvement, Thorax meets Ember is interesting
Cons: Pinkie and Rainbow Dash are more flanderized, Star Swirl was revealed to be a rather loathsome idol of Twilight, no 2 parter intro, lots of fillers, the message for Sugarmac episode was weird at some point
Season 8 :
Pros: Spike has wings, continuity nod from the Movie, good to see Tirek’s and Chrysalis’s clowny sides for some changes, Kirins (the episode has a decent message too prob best of the season), Student Six are ok (Gallus is the most interesting of the six then Yona)
Cons: Cozy Glow, Neighsay as well, fillers, Discord is now being flanderized along with Pinkie and Rainbow Dash, the CMCs are underused, almost no moral lessons new to the series and even as teachers some development backlash, CMCs barely interacts with Student Six saves for Sandbar (Gallus and Scootaloo chicken jokes are wasted in canon)
Season 9 :
Pros: Epic 2 parters at both beginning and the end (even if there is Cozy Glow btw), Fluttershy has many near death experiences in her focus episodes made it thrilling (from a cowardly pony who now grown to face what she feared), CMCs finally learns what it is like to be a full adult (has a good message too), Pinkie has one decent episode (the Cheese Sandwich’s 2nd appearance one has good message), Rarity is more intelligent than ever (except the Dragon Dropped one), The final episode shows the harsh reality that everything can end (better accept it)
Cons: some writing errors (especially Ahuizotl or sudden Rarity vs Gabby), fillers (could’ve use this moment to explore more characters…), RD and Pinkie are still flanderized mostly, Discord became a total controversial character in this season, Cozy Glow’s backstory is not explored in this very season, The final episode may have some character design flaws and leaving ambiguous relationship statuses for fans to think for themselves (which might be also a good thing)