I could argue you're wrong, though. Perhaps not about the animation; sure it's improved if horribly misused across the board. Character animation is great and all, but if my battles are a slog to get through, was it really worth it in the end? I'd argue not.
And storytelling, as @FlygontheRavager
says above is something arguable. Because I find most of the time SM tries to go with an actual plot, it's usually a mess. Necrozma and Aether don't stand the test against other plot-driven arcs of earlier series, and even the other episodes often reek of anti-climax by either just ending or setting up for a battle and turning it into a gag. It's the saying "too many cooks spoil the broth", well, too many references and and storytelling techniques spoil the plot. (I'm also not sure how I can take your word on storytelling when you say the Flare arc was less important than the League just because of who animated it...)
Plus, it just doesn't feel like Pokemon to me anymore. It feels like another show with a Pokemon skin.
To lead back to the original topic, it's why I hardly feel that Ash winning a League in Alola will have any meaning. They don't really care about it here; it's a formality for them to keep that "Pokemon skin" on.
Pokemon wasn't about battles in the first series and it isn't about battles in this series. Pokemon is about exploring the world. Just because your fetish is battles (it's one of mine, too!) it doesn't mean your fetish is the only one that's going to be paid lip-service. Sun & Moon is about exploring the world of Pokemon and Pokemon themselves. We see how humans and Pokemon live together in daily life and even how Pokemon die and the things they leave behind.
Saying Sun & Moon is about battles is like blaming a 4:3 television series for being a 4:3 television series on your wide screen television. Your wide screen television is the one that's wrong, not the 4:3 television series.
Sun & Moon feels different by design. XY was the same. Yajima and Tomiyasu are given series to do with as they like. Hidaka and Sutou were allowed the same during their eras as series director, too. Then for Asada Yuuji's brief stint he too had his own feel. Pokemon is a long-running series that needs to reinvent itself constantly or else you wind up with the Jouto and Hou'en episodes again.
As for the Kalos League over the Flare arc, the Kalos League was definitely Yajima's priority. The Flare Gang arc suffered as a result but Yajima knew that was going to happen trying to pull of a big arc between two other arcs that required all of the best animators he and the production assistants had contacts with. I'm honestly surprised he got Oohashi Aito to work on his farewell episode.
Satoshi winning the Alola League won't happen. Satoshi winning the Kalos League wouldn't have mattered, either. If Satoshi is going to win a League it'll be another Shin'nou League.
And it’s objectively decreased during battles? Funny faces, dances, fillers in general etc have never been the focus of the Pokémon anime and should never be
There’s nothing objective about SM’s plot lines being better than XY’s. There is nothing even to suggest that the animators enjoy working on SM more compared to XY unless you have a citation that doesn’t involve you writing a **** ton about something you think you know everything about
Unless you have a citation saying that the animators think they’re doing better work compared to previous gens, I’m gonna call BS on whatever statements you’ve made about animators
More to the point, this is Ash’s journey and his quest to become a Pokémon master. Winning a league is a huge step to that and it’s obvious that people who don’t care about Ash’s goal will undervalue it
Battles are not the focus of the series. Expressing the feelings of the key animators about the characters through drama and comedy scenes is the focus of the series. I'm sorry you watch the television previews, the Opening and the first 95 episodes and thought that Sun & Moon was about battles. It's not. Tomiyasu loves battles and is quite good at them but his and Matsui Aya's intent is to do something different in comparison to the previous series. Everybody working on the series is quite happy doing what they're doing and when the series eventually returns to focusing all of their talent on battles they'll be good battles, too.
Look at all of the good animators choosing to work on Sun & Moon when they could be working on any other series--because goodness know that there are not shortages of projects in need of good animators in Japan's animation industry. Compare that to Iwane being the only regular good animator for the previous series. Now, compare that to the quality and quantity of the work. You don't produce good work filled with love if you're not enjoying what you're doing. I'm not going to obsessively post every instance of an animator talking about how much they love the designs for Sun & Moon or posting fan art, either.
Animators prefer to work on projects where the character designs are made specifically with animation in mind, rather than being illustrations fit for a piece of merchandise. XY's designs had more lines and shading (awkwardly so in many instances) and made it more difficult for animators to animate the humans moving around. I'm often reminded of how even Iwane would have trouble keeping Alan's clothing from looking like dog doo-doo in motion or even in some stills. Now Iwane can redirect his focus to making characters move or detailed facial expressions.
With Pokemon you get exactly what you see. Sun & Moon is a fun-loving series about life with Pokemon with the occasional indulgence in dramatic arcs and a look into death. If your only criticism is that it's not the thing it's trying not to be then perhaps you should re-evaluate what you're doing with your time. I'd like more people to understand Sun & Moon and enjoy it for being what it is but I can't do that if you're not willing to think outside of your own perspective a little.