Well, I don't want to go off-topic to much, so I'll make a "brief" comment on the various platforms, just in case this could have any value (which I doubt).
Like many who posted above, I don't really like the other platforms (Discord, Reddit), and I much prefer the official forums.
Reddit is ... mostly decent ?
It has a couple of formatting options, which is a good thing, although it doesn't have not as many as the forums.
Once a thread is opened, it can then evolve in kind of the same way as here. I don't think the non-linearity is a particularly valuable feature (if your post C is a reply to post A, your post will go underneath it, and a post B that was chronologically second will not be displayed between A and C). We can handle that sufficiently well in linear threads (what we have on this forum) by quoting the bits we are replying to.
But Reddit (I mean, the BG3 subreddit) does not have sub-forums, to keep General, Suggestion & Feedback, Tech Issues, News, etc, together. I mean, it has tags, but it's not the same. And there isn't one for Feedback.
Overall, I feel it's harder to search for things on Reddit.
And while I don't want to bash too much on the crowd there ... I'm quite impressed (negatively) by the number of people who prefer spending 2 minutes typing the question they have in mind, straight from stream of consciousness to Reddit post, when a 2 minutes search would have yielded the answer. There's a fair share of posts you can help answering by simply providing a link to the FAQ. I guess RTFM has become endangered mindset.
Also, I'm really not fond of the upvote/downvote feature. Possibly, there are subreddits out there, that are not named somethingsomestuff.stackexchange, where posters ask questions to a crowd of individuals with varying levels of expertise (and varying amounts of spare time to write answers), and in the end the best-quality answers get pushed to the top of the thread. But I suspect that in most subreddit communities, some sort of group rule emerges, and posts that irk the majority get downvoted to oblivion, regardless of value.
As for Discord ... no thanks.
Well, firstly, I think Larian set up their Discord server with some specific security settings. Discord wants my phone number before I'd be allowed to post there, so I can't post on this Discord server, Just lurk.
For a while, The Composer was maintaining a nice policy on the Feedback channel : all posts are from player to Larian. You can see what feedback other players are sending to Larian, but you're not supposed to reply to these other players. This probably make feedback just as good and the moderation much easier. I don't know how much this is still the rule. But this is a matter of community and policy, not a platform-related feature.
The Feebback channel was turned from "chat mode" to "forum mode". Which overall is a better way ot organise things.
A major issue with Discord is that its made for chat/messenging. I don't expect that it's particularly good for writing posts longer than a paragraph or two.
A related issue is that, in all the channel that have the original "chat mode", well, good luck following a discussion. I mean, it's possibly for some semblance of discussion to take place. Probably during the night when there are fewer users.
So yeah, forums have their place, in my view. It's not because of the particular community that cristallised here, over the video game BG3, on the BG3 forum. It's mostly because of functionalities.
Although, obviously, these functionalities better support a certain style of posts, and tend to create communities with a certain kind of people.
But for a video game company seeking feedback on their game, I think forum is the best platform/tech to use.
Anyway, digression aside, I'll echo what some have said above.
The forum has always been noticeably slow to open pages.
Some days it's really bad, and pages don't open (timeout, connection expired sort of thingies). But even when it's not really bad, it's really not great.
