I miss traditional message boards. No karma, no sorting algorithms, you just get new topics on top and replies are sorted oldest to newest.
You can have forum threads that go on for decades, but Lemmy’s default sorting system quickly sweeps older content away. I’m aware you can mimic the forum format by selecting the “chat” option in a thread and sorting by old, and you can sort posts by “latest comment” which replicates the old-school forum experience pretty well, but nobody does it that way, so the community behaves in the manner facilitated by the default sorting algorithm that prioritizes new content over old but still relevant content.
I also notice that I don’t pay attention to usernames on Lemmy (or Reddit back when I was on it). They’re just disembodied thoughts floating through the ether. On message boards, I get to know specific users, their personalities and preferences and ups and downs. I notice when certain users don’t post for a while and miss them if they’re gone for too long.
Nested comments aren’t the problem, at least I don’t think they are. It’s how posts/topics are sorted by default that creates a strong bias toward recent content, rather than older content that is still active.
I think there are pros and cons to both nested and unnested systems. With a nested comment structure you pretty much can’t have a single comment that replies to multiple upper comments, you can only reply to one comment at a time. But nested comments allow for branching conversations that don’t derail the main topic.