Did Twitter's 280-character limit improve discourse?
Imo, Twitter's 280-character constraint made ideas sharper and forced people to share high-density knowledge. Not sure it was a good idea removing it as a pro feature
The content beyond the limit still collapses with a Show More; I think it works to still keep things short when they can be short but allow for more explanation for posts that need it. I like the change.
Discourse quality is 99.9999% a trust/safety/moderation policy and tooling outcome. Content can be problematic on any of dozens of dimensions (tone/energy/relevance down to actual criminal consequences) at any size. Whether conversations retain signal and communities develop and grow trust entirely depends on what decisions moderation does or does not make.
I'd argue it's the opposite. It's very hard to express anything nuanced in that space and when you try people go bezerk and call you a "reply guy" or hit the block button or argue with the admins that you should be banned, etc.