In my scoring system, two of the four elements which contribute to the episode's rating are theme and characterization. These are both essential elements of a great episode, but they're meaningless if the episode can't entertain all the way through. "Buckball Season" is a strong example of this, as it boasts fully-formed themes, a relatively strong moral, and some of the strongest characterization we've seen in this show, but none of that can compensate for its eventual descent into tedium which is only slightly mitigated by a strong ending. Add on some particularly weak storytelling, and those stronger elements are only barely enough to save the episode from being outright terrible.
When Applejack enlists Rainbow Dash, Fluttershy, and Pinkie Pie to help her form a team to beat Appleoosa in a tournament for a sport called Buckball, she discovers that the latter two take a natural shine to the sport and demonstrate skills beyond the two more athletic ponies. Excited, Applejack and Rainbow Dash ask their friends to compete for them, alongside the surprisingly adept Snails, who just happens to be walking by. However, their approach to training is to place a lot of pressure on Pinkie Pie and Fluttershy, which causes them a lot of stress, therefore weakening their abilities.
The first question that crops up is exactly how Pinkie Pie and Fluttershy especially become so adept at the game, especially compared to their more athletic and coordinated friends. Pinkie Pie is always allowed a bit of leniency due to her often inexplicable nature, but Fluttershy is a bit harder to justify, and it feels like the two only display greater capabilities because there wouldn't be a plot otherwise. Except, there's hardly a plot as is, and the entire premise comes across as half-baked. Why does it need to be a three-pony team? Why do Rainbow Dash and Applejack need to be excluded? There's no particular reason why this couldn't work if Pinkie Pie and Fluttershy were merely on a team with their more competitive friends, and there's no real reason that they need to be more skilled after barely picking up the sport than ponies who are actually, y'know, sporty. Not only does it make no sense, it's completely pointless.
Applejack and Rainbow Dash want to include a unicorn in order to compete with the unicorn on Appleoosa's team, but why was this component even necessary? It doesn't amount to much other than Snails joining the team to provide brief moments of comic relief, and even this is largely brushed aside. If anything, the early montage of unicorns trying out and failing makes the relative success of Fluttershy and Pinkie Pie even more confounding. Is the episode trying to indicate that a relaxed approach actively works better than a more intense approach? Why isn't there a single unicorn who has the same approach to sports as Applejack and Rainbow Dash? Is all of Ponyville just inept at sports? Why does this episode need to play out this way?
The episode doesn't particularly care about any of these questions, or even about plot cohesion at all. Snips being surprisingly skilled at Buckball comes across as redundant after seeing Fluttershy and Pinkie Pie being the same, it's far from the only thing, as the main interest of "Buckball Season" seems to be endlessly telegraphing its moral. Early on, the episode at least derives energy from the characters' personalities and even a few fun visual gags, but eventually the droning buildup to the moral becomes more and more overwhelming, and when the everything the episode has done for a good five minutes is based around what is so obviously the moral, it becomes a bit of a slog.
The episode might have been a lot easier to swallow if there was anything particularly interesting about the dynamic between Pinkie Pie and Fluttershy, but not only does the episode strain to find common ground between the two, it also has them constantly reacting to outside forces rather than bouncing off of each other. Compare this to, say, Rarity's own dynamic with Pinkie Pie in "The Gift of the Maud Pie," where the two expressed interest in each other's pursuits and jovially bounced their personalities off of each other. This might be the first episode focused on the Pinkie/Fluttershy dynamic, but it gives us less idea of how their personalities interact with each other than episodes which star neither of them do.
The episode becomes a whole lot clearer, however, when its actual moral is considered. The episode states that what works for you might not work for others, specifically in the context of working under pressure, and while this is the most obvious approach to a not particularly fresh moral, it's effective nonetheless, especially in the third act, where the episode's fairly strong characterization is shown. Most of the more flavourful character beats are forced, the worst of which being Fluttershy snapping at RD and AJ with an obnoxious sequence of grotesque facial expressions, but the episode often showcases a relative ability to balance character traits which is only really brought down by the simplicity of the plot and the forced character beats.
This is especially impressive given that the episode has a new writer, as new writers are often prone to flawed or even shoddy character work. The episode never really brings out the best of any of its characters, but it also doesn't compromise any traits, and all four of the main characters present at least feel like they ought to at this point in the show. At the end, the episode really plays on the years of friendship which are now behind these characters, and has the good grace to actually have Fluttershy and Pinkie Pie express themselves to Applejack and Rainbow Dash, and then to have the latter two realize the problem all on their own. The ending, where Rainbow Dash and Applejack realize what they've been doing wrong and show more sensitivity to their friends' feelings, is excellent, not only for how well the characters are able to convey the moral but also for the level of respect and understanding they have for each other. See? There was no need to make the moral so blatantly obvious.
Strong character work and a well-executed moral aren't enough to compensate for the poor storytelling and tedious repetition, but enough of the episode is at least somewhat entertaining to slightly save the episode. "Buckball Season" can't quite rise above its own tedium, and it boasts some of the show's worst storytelling in a while, but it has its moments, and that moral and character work is enough to give it more merit than a lot of the show's weaker elements. It's just unfortunate that this is another simplistic, written-to-moral episode which overemphasizes the eventual friendship lesson at the expense of all else. There might be a great episode somewhere in here, but it's wrapped in too many tiresome elements to properly shine. It starts strong and ends strong, and that lasts just long enough to prevent the episode from being outright bad - but just barely.