I’m gonna go by each part of your response because there is a lot to unpack.
The manga and novels never really added anything major or answered any questions we were dying for answers.
They never needed to. They don’t exist to answer burning questions about the series, but to serve as a supplemental piece of entertainment for fans. Each thing contributes something different to the Kingdom Hearts series. The novels add more insight to the history of characters that didn’t get developed in the games like Vanitas or Replica Riku for example. It also lets us get more into the minds of our favorite characters to better understand their motivations and feelings during the events of the series.
The manga exists to be a fun, humorous, non-canon retelling of the games. The manga is quirky, fun and purely for entertainment.
Should these things not exist because they add nothing to the series? No. They stand on their own and are both an entry point into the series in their own unique way and also serve as another way fans can enjoy a series they love.
The Ultimania interviews do that, yes, but I think for a game that everyone complained you needed to play around 10 games to get the full picture -- add that you have to watch a TV show as well?
I think you are assuming too much about what the TV show would be and what content it could potentially cover.
The reason people complained about needing to play almost 10 games to get the full story of KH was that prior to the PS4 ports, all of the games were spread out on a bunch of different consoles. You had to have either already owned those consoles or bought them specifically to play those games, and so it created a huge barrier of entrance for fans. If you weren’t rich or lucky or frugal enough to buy these consoles, you were missing out on experiencing these stories.
When the ports came out, the issue was that it required tons of time to play through all of the games. If you weren’t setting aside time to play them or didn’t already play them in the past and could speed through them, it was a huge time investment that some people weren’t willing to make.
A TV show is a different thing entirely. The barriers of entrance for them is not so massive. Millions of people are going to get Disney+. It’s guaranteed, and for those who don’t, they will either have friends who let them use their account or there will be some illegal options for them to make use of online to be able to watch whatever shows and movies they wanted to see from the service. This is already a cheaper option than buying a $300 USD video game console and a $60 USD game.
The time investment that would need to be made would be way less than the hundreds of hours necessary to invest in the games. People binge watch series like nothing these days, or it can be put on in the background and watched passively.
I also think that KH would totally lose its magic if you watched Sora in Disney worlds. The beauty of KH is actually experiencing those worlds and you being in control of how you interact with them.
I mean, I can’t put down what you think is part of the charm of KH. That is a very subjective view, but I do feel the need to defend the medium of television and animation.
A good team of writers, planners, designers, and artists can most certainly bring a world alive without the viewer being an active participant of navigating that world. It’s an absolute disservice to any creative talent to think that they couldn’t bring the universe of Kingdom Hearts to life in a way that would still capture the feeling of exploration and discovery in a passive medium.
Why would I watch Sora in Disney worlds playing through a poor rehash of the movie plot when (if I'm looking for something to watch) I can just watch the film?
This brings me back to my point before. You are already assuming too much of a potential animated show. We don’t know what one would cover and how it would tell its story.
I think an animated series would fall flat and lose the magic of KH.
And again, I can’t argue against a subjective opinion but I will defend the medium you are arguing against. Animation is a form of magic all on its own. KH is inspired by that very medium. The whole series a love letter to one of the greatest animation companies in the world, and you think that people employed by said company couldn’t embody the magic of KH?
Not many people paid attention to the manga/novels,
That is false. If the manga and novels weren’t profitable, they would have been canned a long time ago.
but if they put a KH series on Disney + it would be under major scrutiny and on a huge platform to fail and also disappoint.
That’s the risk KH takes every time it puts out a new game, though. To be concerned about KH being under scrutiny when it’s been in this position for years and HAS disappointed many—even now at this very moment people are on FB and Twitter complaining about the series on the official account posts—is a concern you will always have. This will never change.
Your worry about it failing on Disney+, but it could very well fail when the next game releases or the game after that, or fail because Disney and SE end up having a Sony-Marvel level breakup.
I'd rather not have KH be on a list of failures from Disney + and I personally think an animated series would flop because it would lose the magic KH had as a game.
You are already assuming it would fail, and that’s really sad because it sounds like you don’t have confidence in Kingdom Hearts as a franchise and its ability to carry its story and message into a new, unexplored medium.