I'm still waiting for a word back from my friends if we're watching this together so I haven't seen it yet, but based on the pre-release material I've been cautiously optimistic. I'm generally indifferent about live-action adaptations of animated classics, not having seen the Disney ones, but I'm planning to give this one a chance as ATLA has been one of my major fandoms for almost a decade now.
However, I will have to say that the reactions I've seen from the fandom are nothing short of terrifying and downright appalling, and chillingly reminiscent of what I've been experiencing in most fandoms since the mid-2010s. I was already concerned when a bunch of loud people started misinterpreting production statements about adapting stuff for live-action as the creators not understanding the source material and changing core concepts on a whim to the point where obvious jokes mocking the reactions were in turn taken at face value, ending up in people fearmongering that Toph wasn't going to be blind and Ozai was going to be a kind and good dad just because the creators said Sokka's misogyny was going to be presented in a less cartoonish fashion. This might come back to bite me after I've actually seen the show, but oh well.
But the reactions to some of the actresses have left me with a lot of disgust towards this fandom. Some of them have their appearances constantly mocked, ranging from nitpicking about "completely different face shapes" than their animated originals signifying miscast roles (counters about acting like a character being more important than looking like them being shot down with blanket declarations of them being bad performers anyway, so "they could've just as well cast someone who at least looked the part") to outright fatshaming them due to their round faces, which would apparently ruin the verisimilitude of their future fight scenes. And then there's Katara's actress who has seen her Instagram be flooded with a torrent of hatred, pegging the apparent catastrophic failure of the series solely on her for apparently being a bad actress, some even demanding that she not only quit the series but retire from acting altogether.
I was toying with the idea of joining the main subreddit so that I could join the revitalized discussion, but that community is basically a huge dumpster fire now. Any and all discussion of the franchise is completely drowned out by a constant stream of posts all declaring the show to be an unwatchable and pile of crap that ruined their childhoods (with an omnipresent misuse of the word "objective" that shouldn't surprise anyone), calling people who like it mentally challenged, with some people visibly grasping at straws to find reasons to hate it (some even complained that the costumes not being dirty enough ruined their immersion) just because it's trendy to do so. All in all, I find it extremely reminiscent of the Star Wars fandom after The Last Jedi came out, complete with the original creators being put on a pedestal as though the fans haven't been spewing all kinds of vitriol at them because they blamed them for everything they hated about the previous installment of the franchise.
Someone said on a different subreddit that they just can't participate in fandom subreddits anymore as they're all filled with the same kind of hate-everything mindset drowning out everything else, and I have to agree with them. I mean I've learned not to mention Rey within earshot of Star Wars fans a long time ago. The inevitable fights are just not worth it.