One thing to consider is that there isn't a lot of widely-accepted verbiage with regard to this particular topic. While I'm sure there are various conceptual frameworks that have well-established terms and definitions, the makeup of what constitutes "canon" with regard to imaginary realms that are presented for public consumption isn't (to my knowledge) one of them. Which is to say, I think that some people - potentially a lot of people - are trying to express this view, but are struggling to articulate something that's largely intuited.
Secondly, the issue of the conceptual space not being "sufficiently" defined - where "sufficiently" is entirely relative for each individual - isn't going to be limited to issues of plots and storylines. Or, for that matter, areas of fictional geography, character backstories, future histories, etc. The same way that each individual decides for themselves what their point of personal saturation is, they also get to define what constitutes how that point is reached (for themselves, I mean). It might be something like "they just de-legitimized the framework we had for understanding what life was like in Unther prior to the Battle of the Gods," or "does that undo how the drow servants of Kiaransalee were taking over the Underdark beneath Vaasa and warring with Orcus's servants there?" Or even just "there's no longer an understanding that Aurora's whole realms catalogue was ever a thing now."
Each person gets to decide for themselves where their personal fill of canon was met, as well as how.
Sure, each person has their own individual lines... but that also kind of ties into what I'm talking about.
Did they de-legitimize the framework for Unther? We don't have a replacement framework, so I'd say that the pointing to the best current framework is still legit, until they do something that disrupts it.
Does that undo the fighting between the Drow and Orcus? I don't know. They didn't say that it did, so any changes for or against are your choice unless they publish something new.
Do you mean there is no understanding that the physical product existed in the Meta? Cause that is blatantly wrong. Are you saying that there is no understanding in the realms? Well, there can be unless they publish something new to change that.
That's the thing I think people are overlooking because of the highly emotional response. This announcement was an announcement of a willingness to change. It was not an announcement of changes. If they never touch on Vaasa again, then nothing ever has to change from the previous canon.
It wasn't meant to be read that deeply. Rather, the point was that it's a situation where nothing practical has changed, but a conceptual realignment of things (i.e. who sits at the top of the political food chain that you're at the bottom of) can still be taken very seriously by some people, for understandable reasons.
Fair, but the only conceptual change is an appeal to authority. That is literally it. The material doesn't change. The way you can choose to use it hasn't changed. The only change is that stamp of approval from WoTC that they support your vision of the truth.
And that is very much the least important thing if your goal is to continue using what you have always used.
This is where we get into definitional issues. I wouldn't call fanfiction - i.e. fiction based directly on another property, used without permission - "canon" in any sense. A particular piece of fanfiction might have a structural framework on its own (i.e. its own internal consistency regarding itself as a story), but it's ultimately dependent on the material that it's making use of. Hence, further changes to that material can change the understanding of what happens in the fanfiction. While things like AUs (alternate universes) that alter some aspect of the underlying foundation might seem to step outside of that, they're still dependent on the things that haven't changed to give them part of their identity (and likewise, what parts haven't been changed can thusly be understood differently should the source material change).
Complete disagreement.
Canon is "the agreed upon history, lore and rules of fiction". Every Fanfiction has its own canon. It is just not the canon of the main product.
Think about Into the Spiderverse for a moment. Canonically Peter Parker isn't the Lizard in the most of those realities... but in Spider-Gwen's reality Peter Parker was canonically the Lizard and was killed by Spider-Gwen.
So, if I said "canonically Peter Parker is the Lizard" I'm right... as long as I'm talking about that reality. If I say "Peter Parker is Spider-Man in the Canon" I'm right... unless I'm talking about the reality where is it Miguel O'Hara.
Now, you could try and argue that the "true canon" is that "Peter Parker is Spider-Man, except in Earth-928 where is it Miguel O'Hara and Earth-65 where he became the Lizard" But that only works because Marvel and Spider-Man are constantly working in multiple universes and connecting those universes together.
To take another stab at it. Did She-Ra and Catra grow up together? 1985 canon is a solid no. 2018 canon is a definitive yes. Is one "more right"? I don't think so. They aren't the same story.
I think we're in danger of confusing which mode of engagement we're talking about, here. As I mentioned previously, the understanding of a particular canon with regards to simply taking it as a stabilized realm of imagination is a different mode than interacting with the component lore in your tabletop campaign. The latter (i.e. using it in your game) could be said to deviate from canon almost by necessity, since the actions of your group will introduce alterations to what the canon has already established (though the scope and scale of those alterations are something else altogether). That's different from what we're talking about with regards to why people feel that canon is important unto itself. (And works as another reason why I think that the term "canon" - being necessarily external to an individual's participation in the lore - loses some of its meaning if it's applied to unauthorized derivative works; please note that I'm using "derivative" without any sort of pejorative undertone).
Again, you're talking about gaming as a mode of engagement, rather than the mode you'd apply to a body of lore unto itself (i.e. a set of novels, a particular TV series, a comic line, etc.). Those are things where "canon" as an idea helps to define and better understand the shared nature of the imaginary realm. Your personal D&D game isn't shared - except among you and your friends - and it's not grounded to you, since you've assumed control of the framework involved. So talking about "canon" in that context seems to me like a misapplication of the term.
But I think that the two can't be seperated that cleanly. By engaging with RPG canon, you by necessity have to change it, so having an entire set of canon that isn't true anymore is kind of the default state. Orcus is alive in Canon. If you kill him, you have changed Canon. And that isn't something people are upset by, in fact, they are eager to try and kill Orcus, despite it irrevocably harming canon.
And from that context... I don't see how WoTC's declaration is any different. Whether or not Orcus really did try and kill the Raven Queen is a much smaller issue than the fact that your gaming group killed Orcus long before that event even happened.
