I'm typing this up before I finish this thread, because I want to touch a little bit more on the ideas expressed earlier about the differences between changes that are additive and those that are destructive. I'm going to be talking about a few different IPs that not necessarily everyone knows about or likes, but I think they run the gamut of showcasing the different types and reasons of changes that accompany reboots.
And I want to focus on reboots because I think that these are the biggest pain points with regards to canon. No one really has debates over the canon of say, Brandon Sanderson's Stormlight Archive, because there is only one body of work by one author. It is when things start changing that things get whipped up into a froth.
Now, first off, are all changes forever bad and wrong? Obviously not. Not following canon doesn't make a piece of media bad. I know these are "kids media" examples, but She-Ra and Carmen San Diego got reboots that were incredibly well received. Did they change canon? Absolutely. I haven't watched more than about three episodes of either, but I will guarantee you that they utterly ignored canon over and over again. And I think when you are doing a reboot, that's healthy to a degree.
You can't just repackage the same story and re-release it with new actors or new art. You have to change something. I was going to talk about the anime Full Metal Alchemist (which I do want to touch on anyways) but I'm also reminded of remade movies like True Grit, or actually there is a very strong example of this in the story of Moses. The Story of Moses has been told and retold dozens if not hundreds of times. And each take is different. The Prince of Egypt is not The Ten Commandments, and that's a strength.
There is however a... quirk that I think Full Metal Alchemist highlighted for me, though I can pull in other media that does something similar. The original Full Metal Alchemist TV series was very good, amazing even. Engaging characters, complex world, deeply compelling plot. And years later I discovered they had done a reboot of it, which shocked me, called Full Metal Alchemist: Brotherhood. And it was vastly different. Key, fundamental aspects of the original plot and the original story were gone. And, I later learned that this version of the story was closer to the original books. And I love it. It was actually far better. It was grander, and frankly I'd say almost every aspect of it was better (personally). But, watching a review of the series and a comparison, a reviewer pointed out something that I didn't notice. In the original show, they spent about... 20 episodes let's say, on the first few plots. They really dug into those plot lines and they were significant for the show... but in Brotherhood these same plots were handled in around 8 episodes. It was incredibly fast-paced and frankly done in a poorer manner than the original.
The reason that I didn't notice this is the same reason that the studio likely did this... because we all already knew the story. This wasn't a reboot ten years later or anything like that, it was fairly recent from the original and the studio figured that the people who would come to watch Brotherhood, likely already knew the plots from these episodes, and so they condensed them, to rush forward until the point where the story started diverging. I'll note that the new Spider-Man movies have done something similar. The MCU Spider-Man doesn't have an origin story, or Uncle Ben. We just sort of start in the middle. Which... is perfectly fine. We don't need to show the story everyone knows, even with slightly different details, because that part doesn't actually need to be shown.
So, with all that said, where do we have instances of Reboots gone bad? Where are the troubles? Well, I want to start first with two movies that I will never see, because of how much I hate what they did to franchises I loved. The Last Airbender and Eragon.
Both of these movies could be argued to be bad because of the changes to canon. The Last Airbender made significant changes to the canon of the original show, some which may seem minor to people not familiar with the material (such as firebenders not creating the flames they use) others which everyone would agree are radical changes. However, it wasn't just the changes to the canon that were bad, but The Last Airbender would also fail the "know nothing" test. Which is, even someone who knows nothing about the canon of the original can recognize that The Last Airbender is a bad movie. The special effects are bad, the pacing is bad, the acting is bad. You don't have to be a fan to see this movie and say it is a bad movie. So, why do we even talk about canon with regards to this movie? I think because we feel it is indicative of the reason why everything else failed. Because these changes weren't seemingly made to tell a different story.
See, Carmen San Diego's reboot changes just about everything about the character, but it was done because the studio was telling a new story, and many of those changes were necessary for that story to function. They couldn't tell the story they wanted to tell, without making those changes, but in the case of The Last Airbender, many of those changes were for "realism" to make this world seem more consistent or real or fair. They weren't made with a story purpose in mind, they wanted to tell the same story, but they want to tell it in a way that is faster or that "corrects" the original without seeming to ask if "correcting" it is the way to go. If they are actually doing more harm than good.
Which brings me to Eragon briefly. I don't actually know if Eragon passes the "know nothing" test or not. No one even talks about the movie, so I'll assume it was a bad movie anyways, but it does something a bit different in its changes that is worth bringing up. See, Eragon the book, is book one of the a four book series, and so you'd expect that the movie would have a sequel, right? Except... it can't.
The plot of the sequel book is kicked off and revolves around two characters known as "The Twins" who were introduced in the first book. They are vital to the plot. In the movie Eragon.... they were killed off. And the entire movie was done in a way that meant that the planned sequel, the planned story cannot possibly go forward. And, if I had to guess, this wasn't on purpose.
I'm going to call this being careless with canon. See, if you know the canon and move forward to intentionally change it to tell a new story, then generally it can work out. Whether or not your product succeeds then is based almost exclusively on the merits of the piece. But, if you change canon out of ignorance or a lack of care towards the source material, you can end up ruining the story. Because you aren't trying to make something new, but you stumbled face first into either being required to make something new or making a mess, and many many people end up making messes.
There is one last thing I want to talk about, and it mostly goes beyond the ideas of story that I've been talking about. Devil May Cry is one of my favorite game series. Love it, it is really good. And, a few years back, there was a very controversial reboot of the series in the game DMC. Most of the controversy of the changes centered around the changes to the main character, Dante, because the game play was actually mostly unchanged.
See, in classic 90's style, the original Dante was a wise-cracking almost campy anti-hero. He was goofy at times, he went to bars and ordered strawberry parfaits, and his design was sometimes over the top, white hair, red coat, ect. He also had that edgy backstory. He was a demon hunter whose father was a demon who had fallen in love with a mortal woman. And I know, there is some camp and some cringe in this character. He wouldn't really work as a modern character.
And the changes to him in the DMC game were extensive. Instead of being a late 20's early 30's wise-cracker, he was a foul-mouthed teen. Instead of buying pizza or getting a strawberry parfait, the game opens with him having sex with a succubus in his trailer. Instead of being the son of a demon and a mortal, he is the son of a demon and an angel. And they made him dark haired.
I keep mentioning the hair, there is a reason for this. But, if I'm brutally honest, the majority of the changes aren't exactly bad on their face. Yes, I think opening with a sex scene and the constant foul-mouthed cussing are just stupid and trying to hard to be edgy, but if the game had been good I would have maybe forgiven them? And the game play is certainly good, the story is just... way too try hard edge. Even if they didn't mangle a beloved character, it wouldn't have gotten far.
But, the controversy over the changes certainly got to the creators, because they did something that I think people often accuse creators of, but that I rarely see. They mocked the fans.
See, early on in the game, New Dante is thrown through a building and as he stumbles out he sees a mirror. On his head, perfectly placed, is a white wig that makes his hairstyle look exactly as it originally did. He then says something to the effect of "Yeah right, not in a million years" and throws the wig to the ground while staring directly into the camera. It is blatant. And I can understand the Schadenfreude of wanting to hit back at the rabid fans who hated these changes... but it is also petty and attacks the older character.
And I know, this sort of accusation occurs all the time. Plenty of people accuse creators who change the canon of hating the fans, or insulting the old fans, or giving fans the middle finger. I bring up this example because, to me, this is what that actually looks like. Looking directly into the camera and saying "No, your thing is stupid". And, yes, it is a hard line to walk knowing whether the changes are made in this sort of pettiness... but generally it is blatantly obvious. And if your argument is that it is an insult to change things... no, it isn't. Changing things alone is not an insult, in fact, it can be a compliment to the original. "Your work was so good, I want to make my own version of it, but I want to make these changes to tell this new story" isn't spitting in the face of the old work, it is celebrating it.
So, sort of in conclusion, I think this can all be summed up in some oversimplified ideas. Not all changes are bad. Changes to create a new story can be really good, and done with love towards the original. Careless changes that seem to serve no new purpose are not a good sign. They aren't attacking you unless they are actually attacking you, if you can point to something direct and explicit, fine, but if it is conjecture based on them simply changing things, then you likely aren't being attacked.
And most importantly, take a chance to ask non-fans if they think the material is good. Not if the original is better or worse than the new version, just simply if the new version is good. If someone who doesn't have nostalgia for the product says it is trash... it is likely trashy. If they say it is good, then while you may even be right that the original is better, that doesn't mean the new one is bad. No one can make lasagna like my grandmother could, that doesn't mean all other lasagna is trash, they just aren't as good. Maybe Tolkien's Middle Earth is the best, but that doesn't mean that the new version is bad, it's just a different take. Looking to explore different ideas.