For Kingdom Hearts if it was just the original story segments, but more fleshed out would any of your issues be fixed? Maybe not because of what I was saying earlier. Kingdom Hearts stories are definitely not for the faint of heart. Definitely one of the hardest stories out there to piece together and master. So it's difficult, but it doesn't immerse you, so you feel stress instead. Context is everything, as you say. It's like the difference between running on a treadmill vs running for your life because a dog is chasing you. It;s the difference between lifting weighting, and swinging a heavy sword to defeat these robotic pirates. I would LOVE getting exercise if it meant I got to kick ass! haha. 

My enjoyment of Kingdom Hearts is not because of emotions. I enjoy how mentally stimulating it is. I don't have a difficult time following its plot and it does immerse me. You can animate, but I can follow kingdom hearts. Different brains, different talents, different skills. You can't change it from that difficult storyline without ruining it for someone else like me, but there are things they could do it make it more user friendly. They could add some more details to make it more immersive, sure. That wouldn't hurt anything. If all you want it to actually have some people in Pete's audience when he's giving a lecture, or people at Cinderalla's ball then sure! Why not? That's just then being super lazy about telling the Disney world's stories because they don't personally give a crap about them, but people like you are a good reason to put effort into them. They could satisfy both casual and hardcore gamers by putting more effort into the disney world plots. There could be multiple reasons for enjoying the game instead of just one. If the disney worlds told interesting stories in their own right and were filled with tons of characters to interact with. You could get immersed and play the game for just that and skip the cutscenes of the main plot. Just to experience the Disney movie first hand in video game format. You get to explore beast's castle first hand. You get to swing on vines like your Tarzan. You get to resolve the war in China through to diplomacy only to discover that Goofy betrayed you! 

So yeah i think that's what they could do to please both fans of Disney and Final Fantasy at the same time. Make and fill the disney worlds with more standard plots and devices, like romance, friendship, and betrayal, whatever you would consider interesting, and then keep the main plot in it's convoluted and stimulating place that it is for us hardcore fans. I don't mean to insult you because you say you want reality and that's the reality of the situation. This game's story challenges you in a way you don't enjoy, you hate figurative speech. You're not the only one though. Plenty of people are into kingdom hearts just because they're disney fans, so they could stand to throw you all a bone and not be so dismissive of the plot of the disney worlds. They could put some time into making those good too instead of just the main plot.
This is what I've concluded. Kingdom Hearts is divided into two fan bases. Casual Disney fans and hardcore final fantasy die hards. It did a good job of delivery on its promise of exploring your favorite Disney worlds first hand in the first game. It had a vine sliding mini game in the Tarzan world, there was a magic carpet ride segment in Aladin, and you flew in peter pan. But after that they got lazy. They stopped putting so much work and effort into fleshing out the disney worlds. They became hallow shells of worlds that got sacrificed to serve the main plot. Sp after the first game they disrepected and turned away the more casual fan base. People like you or Clement. He said that the first Kingdom Hearts game was the only one he liked. For the similiar if not the same reasons as you. The plot got a lot more intricate. What they can do moving forward is go back to a style like the first game. Make the disney worlds interesting again, and MAYbe tone down the difficult of the story a tiiiny bit. Just a little. The first game isn't nearly as hard or complicated as the others.  

Wanted an explanation for light and darkness

On your point about Light and Darkness, the assumption is that most people know right from wrong by nature. Or if not then they've at least learned from others. But also the specifics of morality can be a very sensitive issue, culturally, politically, and personally. So their vague approach is a safe one. An attempt to inspire people towards loving emotions, and good behavior which the writers assume most people are capable of judging correctly. That's an out of the world explanation though. There actually is an explanation of what light and darkness are actually in the universe it's just subtle and you have to those small pieces and connect them together yourself because the story doesn't spell it out right to you. In the Kingdom Hearts universe Light and darkness are literally the energy force that people's emotions (or planet's emotions will get to that) produce. If you feel emotions such as happiness, sorrow for another's pain, or love then your heart emits light energy. If you feel anger, lust, greed, etc. then your heart emits dark energy. Light keeps you normal and healthy while darkness more and more sickly until you turn in a heartless. Or rather your heart becomes so full of darkness that it leaves your body altogether and becomes it's own shadowy being called a "heartless." Your body itself gets left behind and exists merely as an empty shell called a "nobody."

You're right in the sense that whenever Sora or Ansem gives these speeches about light or darkness, it is sort of fourth wall breaking. It can seem like some vague illusion to morality and it is one level, but you can also see how it affects the story in universe. Ansem has a lot of dark energy, it's a tough fight. Shouting out his little speeches gives him motivation and the energy to get through the difficult situation. That's for Kingdom Hearts 1. For Kingdom Hearts 2 things do actually start to get deeper. The debate with Xemnas at the end of Kingdom Hearts 2 is Sora and mickey starting to experience some cognitive dissonance. "Why are certain emotions so bad?" That is what Xemnas asks of them and you can tell by Mickey's answer that he doesn't truly know, "It's just so dark and scary...." a cop out answer a superficial rationalization to maintain a belief that he's always assumed for be pure fact. The fact that Riku was able to wield darkness ( again literally the energy emitted when people in this universe feel angry) for good purposes does give them all moment for pause. Maybe what they've assumed was true about light and darkness, positive and negative feelings, right and wrong was not as true as they thought. That they only had a superficial understanding and that there was more to life and decisions than it seemed at first glance. 

In the end, Kingdom Hearts hints that there should be a balance of positive feelings and negative ones. I am pretty sure the plot of the third game will end on this conclusion. If I remember correctly the point of the keyblade war is to bring balance to light and dark energies and reconnect all the worlds back into one pangea. Or Xehanort is trying to destroy all the light energy in the world because so he live in a world with only cold calculating emotions instead of joyful cheerful ones. But Disney owns Star Wars now, so maybe we'll find out that Xehanort is actually darth plageus, master of the emperor, and he's planing on using the dark side to live forever. I think that will be his true motivation in the 3rd game. Maybe in a world with only dark energy he will live forever, but if light energy co-exists he'll eventually die.

Is this line of commentary more relevant to you? I want to be as on point as possible to what you'd like to discuss. If I'm not hitting the topic you want just let me know.