Surprisingly, I agree with about 90-95% of this. The only one I outright disagree with with is number two, while the others, I don't so much disagree with the concepts as a whole, just bits and pieces of them. Which I will address and explain why.
#7 Escalation
The specific part I'm iffy about is death. More so, the reasons why characters should die in relation to villains. Over all, my sentiments are just the same: I don't think death should be added for the sake of death and to make it more grimdark 'cause that's dumb. It's dumb-de-dumbdumbdumb. Actually, I'm not adverse to characters being killed off given it feels natural to the story, it's not a case of me not wanting my favorite character to be axed off. I just feel that the villains killing off characters to show how bad they are is kind of a generic display of evil and undermines everything else they (especially Xehanort) has done.
As far as we know, Xehanort has only killed one person, someone who he grew up with, lived with, and regarded as a "brother". ME may not be a main protagonist or one of the older characters, but MX killing him off speaks way more of his of character and what he's willing to do to attain his goals than if he were to, let's say, kill off Riku. It might hit the audience harder, sure, because there's more reason to care about him, but the fact that MX is willing to commit murder in the first place I think is enough to show that he's a threat. Not to mention there's the other things he's done, like torture, body snatching, child endangerment and neglect, acts of genocide (I use this term loosely), kidnapping, illegal human experimentation, and the list goes on. Xehanort may not have a trail of bodies, but I think he has done more than enough to show that he's a threat.
#4 Kairi, I mean seriously
I'll admit, I'm one of those people who've nearly given up on Kairi's character. The only reason I haven't yet is because there's one more game left in this saga and since they're teasing a bigger role for her, I'm willing to give them the benefit of the doubt for one more game.
I disagree with is the complaints of Kairi being a completely helpless DiD are completely unfounded. Or they're founded. They're VERY founded. The rebuttal is that because Kairi has moxie and is willing to help without asking for help, she's really bad ass. Which I've give credit for, if there's one thing Kairi has, it's will power. For better of for worse, Kairi will throw herself into a situation and put her life on the line without a second thought if it means helping her friends. She doesn't whine about it, she doesn't over think it, she just does.
My main issues with Kairi though can be chalked up to two broad problems though: I think she's poorly written AND not fleshed out enough.
It's not just that she doesn't have enough screen time and hasn't been developed much, it's that I think the little we do get isn't well written. She was okay in KH1 because she at least had a personality and a purpose (albeit, it was extremely passive), but in KH2 she seemed to be molded to be a "perfect girl(friend)". What little tomboyishness and spunk she had dissipated so that instead she could stand around dramatically with long hair blowing in the wind and a skimpy diddly me dress. She doesn't speak or do much, and when she does, it's almost completely related to Sora. She doesn't want to hang out with friends unless they talk about Sora. She doesn't want to go to places that used to make her happy because of Sora. When she meets new people it's to talk about Sora and their "romantic" exploits. Her only future goal is Sora. Her one true motivation is Sora. The only thing that occupies her mind and dictates her actions is Sora. The reason she would die is for Sora. Even her not asking for help is for Sora because she doesn't want to put him in danger. Oh, and Riku's kind of, sort of, important too, but not really.
It was mentioned that Donald and Goofy should go with Kairi on a journey where they talk about Sora, and I think that's the last thing they should do. First and for most, I'm frustrated with Kairi as a character because she has so much potential. She's a Keyblade wielding Princess of Heart, who's a Guardian of Light and indirect successor of the mage and Keyblade Master, Aqua. Yet, they keep defaulting to her being "the most important person to Sora". Kairi over all just needs a break from Sora and given a chance to sort out other important things, like MX, the new Org., the people in torment, etc. She just needs to focus on something consecutively that's NOT Sora.
#3.5 Multiple Playable characters
A totally different character for the tutorial. This is something I mentioned a long time ago, but I think starting off the tutorial with a totally different character defeats the purpose of having a tutorial in this sort of game. KH is a series were all the characters have unique fighting styles and skill sets, unless they're similar for plot reasons. The purpose of the tutorial is to ease new players into the game, and assumes that everyone is playing for the first time. With the characters all having their own unique abilities, none of the games have really switched off characters like that. In every KH game, with exception of KH2 and bonus stories, you play as the tutorial characters for the rest of the game. The perceived quintessential tutorial character for KH3 is Kairi, but unless she has a very similar play style to Sora, I don't think they'll use her (or anyone else whole would play drastically different). I'm assuming she'll have a style all of her own and switching from her to Sora would just be jarring.
#2 Final Fantasy Worlds
It's already been long established that all FF characters are different incarnations from their respective game selves and inhabit either original or Disney worlds. They could get away with implying that we might see Shibuya because it's a totally different franchise, but I think it would seem off to have some FF characters completely integrated into KH and some others just not. Besides, Nomura made that decision because the involvement of the FF characters is a complete "what if" scenario. Unlike with the Disney characters, he wanted to see what would happen if he took all the FF characters out of their environment and out them in almost completely different lives. Which I'm totally fine with. With Disney, it's a story of what would happen if outside forces invaded their worlds. With FF, they're an outside force adapting to Disney.
I think that pretty much covers it. Other than these issues, I agree with everything else. It was a very insightful video, which is more rare than it should be. The person who made the video promises to put out more KH related ones and already has some up which gives me something to look forward to.
P.S. I want some of the content in the manga to be included in the games as much as the next person, but it's unfortunately not canon. I prefer manga!Kairi to game!Kairi too, but I hope he's not holding it to the same standards.