Well, let's put it this way: the KH series would NEVER have survived if not for being a video game franchise.
Now, here's what I mean by that: The series is terribly written in many places, and fantastically written in others. But it's very hit-or-miss. Luckily, whenever the story falters, the gameplay and the general aesthetic of the series can usually carry the slack because of how fun and enjoyable they are. I like to think the "bad" moments of writing are actually quite self-aware, the series making fun of how ridiculous its own concept is. But every now and then, the writing does decide to treat things seriously, and it's those moments when it shines. Unfortunately, from what I can tell, these moments feel much rare and more far between than they used to.
Take the case of the first four titles for example: KH1, CoM, and KH2, and Days. These were the games when the series' writing was at its best imo. Nomura had a certain magic touch back then that he seems to have lost nowadays, and that mostly refers to the way he not only wrote the story, but the characters.
KH1, for example, was really great at writing Sora and Riku's characters. Especially Riku. The sense of superiority, eventually corrupted by betrayal and abandonment, was one of the best villain arcs in the series in my opinion, mainly because he was so relatable, and it perfectly fit into the first game's theme of growing up and expanding your horizons, which is not always a wonderful or pleasant thing to go through. Even the little time we got between Sora and Kairi felt more real than all their interactions have since then.
Chain of Memories was another great example of how Nomura used to write characters. I'd go as far as to say that Sora probably had the best character arc in that game, which almost makes it a shame that he forgot all of it. The way the story played with false memories, with self-doubt and obsession, was really well handled, and seeing Sora actually get driven to the point of hatred is something we haven't seen since in this series (would have liked to see that after Xehanort bodied Kairi, for instance).
I've written about how people give KH2's story way too much of a pass for how cluttered and unfocused it is, and how unnecessary most of the Disney worlds are versus KH3 where I feel they implemented the worlds into the plot much better. However, the opening prologue section of KH2 with Roxas to me is still the crowning glory of the series from a writing standpoint. That whole section is a story in itself, and it's a wonderfully told mystery about a boy who suddenly finds his entire world being turned upside down and losing all control over his own life. That shit is extremely relatable. And it was one of the few points in the series that weren't hampered down by all the light-heart-dark nonsense, or the increasingly convoluted plot.
Days, of course, is also great. The relationship between the Sea Salt Trio is one of the best explored relationships in the series, and Roxas' personal growth and learning about the world was perpetually enticing.
In all those games, there are plentiful moments when the writing just gets downright ridiculous, as well it deserves to. This series has always been ridiculous since its conception. And it's healthy for the series to poke fun at it. But the characters were what gave the games a real sense of emotional weight despite how bad the actual dialogue or storylines would get at times.
To me, Birth by Sleep was where the writing started taking a turn in the wrong direction. Now, I know a lot of people love BBS, but hear me out:
To me, the relationship between Terra, Aqua, and Ventus never really reached the same level as the relationship between the Destiny or Sea Salt trios. Their whole dynamic was just not that relatable. Terra was a strangely written character who we're told is supposed to have a lust for power, but they never really show it in any significant way. On top of that, having a lust for power is a very anime motivation for a character to have, and it doesn't have the relatability or emotional charge of, say, turning against your best friend because you feel he's outgrown you and getting better than you (they actually COULD have had that dynamic between Terra and Aqua, in fact they seemed to set it up, but they never actually do anything with that). Aqua is another heavily anime-ed character, who's simultaneously supposed to be the "girl" of the group, but also the "mom" of the group, if that makes sense. Ventus, meanwhile, is just a bright-eyed and naive kid. Despite the constant lessons they each keep learning in the Disney worlds, I never get the sense of them actually developing as characters. From the beginning to the end of the game, they all mostly just turn out more or less the same. Not to mention, I actually think Xehanort and Vanitas from a writing perspective are actually poorly handled as the main antagonists in this game, with neither of them getting very interesting insights into their character, their experiences, or their motivations. They aren't like Riku, who most people who've ever felt abandoned or tossed aside by their friends could sympathize with, nor are they like Xemnas, who was a really tragic character who was willing to commit atrocities just to become human (at least, that's as far as we knew up to that point). The Xehanort Reports belie a deeper character full of scholarly obsession and unfulfilled ambition, but we never actually SEE that side of him in-game. In fact, the Xehanort with the evil grin and the wiggly fingers feels like a different Xehanort to the one who's writing those reports. The Xehanort we see at the end of KH3 actually feels more like the Xehanort in those reports tbh, and that's part of the reason I enjoyed that scene.
Coded doesn't have much to speak of either in terms of story or character, and DDD, well, that whole game narratively was a mess. Even if the plot weren't a massive dumpster fire, I honestly don't think Sora or Riku really evolved that much over the course of the story. They ACT like they did, but really, there was very little actual development. The same with KH3.
And with each of these games, I've noticed the same pattern—just like the earlier games, each of the worlds the characters visit is used to teach them some sort of lesson. But ever since BBS, those lessons have felt more like substitutions for actual emotional struggle and development rather than supplements to it. In KH1, CoM, KH2, and Days, each quest and each world you visit felt like it added to the characters' sense of themselves and their relationships with one another. Sora and Riku's relationship continuously devolves from Traverse Town, to Monstro, to Neverland, and Sora's relationship with Donald and Goofy goes through its own series of evolutions, as well as Sora's sense of his place in the larger world. In CoM, each world, even though Sora forgets it after he leaves, feels like it leaves a lasting imprint on his identity and on his psyche. KH2 constantly plays around with Sora's sense of himself and how Roxas is secretly affecting him from within him. And each mission in Days plays into the developing relationship between the Sea Salt Trio. In each of these games, the worlds act more as bricks to the main story that constantly build on top of one another. There's a sense of progression in them, and therefore cohesion. But in BBS and DDD, each world feels like isolated from the main story. They don't play into it. And so even though they claim to learn these lessons at the end of their visits to each world, we never actually see how those lessons change them throughout the story. They feel like disconnected moral lectures that get immediately forgotten. Because in the later games, the characters revolve around the plot, and not the other way around as it should be.
So, when you DO get to those later games, the "bad" writing stands out a LOT more, because there isn't as much of those emotionally resonant wow moments to lend any gravity to it. Now, even when the story tries to be serious, it still ends up feeling silly, because all the characters know what to talk about anymore is the PLOT. Darkness, heart, light, memories, data, Keyblade. It's a different Ansem who says "So, you have come this far, and still you understand nothing?" from the one who says, "Darkness within darkness awaits you!" Yes, they talked about darkness and hearts and light all the time in the first games, but then they were tempered by deeper messages and characters, whereas in later games that's pretty much all they talk about ever. There's nothing underneath it all anymore. That's why I liked Xehanort's death in KH3—it was the first time I ever saw the HUMAN BEING underneath the hammy evil one-dimensional Palpatine mask. That scene was the first time I saw a man who had spent his entire life since his youth obsessively in search of a single ambition, who was willing to commit his soul and his humanity, who was willing to sacrifice everything good in his life to fulfill that ambition, only to see it all ripped away at the very end. That one scene of Xehanort to me was better than the entirety of his character throughout all the rest of the games, and you can fight me on that. I don't even care if it was inconsistent, it was better. It made me SEE the person that I think Nomura always wanted us to see, but he never managed to actually write him well enough.
It's moments like that scene that give me some small hope that Nomura can reclaim his magic touch, and it's partly that reason why I'm actually glad he's taking the next 2 years off from the series. Hopefully, he can come back fresh and having regained that special emotional resonance that so thoroughly permeated the earlier games in the series, because it's those moments that made those games truly magical. The plot is fun to speculate over as it continues to develop, and yeah, the Master of Masters is an interesting villain, but speculation is no substitute for feeling. If this series is to return to the magic it once had, the plot needs to be refocused around the development of the characters again—the characters have to think about more than just the quest and the battles. They have to think about each other. They have to have real heartfelt moments with each other. And they need to go through relatable, emotional struggles to make them grow, rather than just leaving their growth to sequences of pithy moral lessons and superficial conflicts.
Wow, I wrote a lot. Sorry.