Either way, despite how polarized it may have been, it was valuable for many groups and a large number of genuinely grassroots social & artistic movements originated there or effectively used it. Destroying those doesn't seem like a clear cut positive for humanity, as you're framing it.
You can't have an actual discussion with such a small character limit. However it's easy to spout off nonsense bullshit in a small character limit. And then no one can really argue with you because it takes more words to actually back things up. Thus it's really easy to spread bullshit and the people who are more susceptible just eat it up as they can only stay focused for a few sentences anyway.
TikTok was kind of the same way and it drove me crazy up until the last year, because the comment limit was so short (and the fact that you can't really see a thread properly, just like twitter.) The user base of tiktok seems to have vastly changed over the last year (or maybe they keep improving their algo so much I just don't encounter it) but I've gotten used to the limit because people aren't arguing as much they are just genuinely commenting on a video.
I was always a fan of Reddit (until recently) because it was just a message board- you could actually read real thoughts and have a formatted threaded discussion (like on HN).
I think social media itself is the problem, not the post length.
Letting everyone talk is free speech. On the street you walk away from the lunatic, but with social media they find their kind and yell together.
Which one would the social media algorithms promote?
I credit algorithmic timelines as one of the primary factors in today's hyper-polarization. Twitter was one of the more influential ones, especially when coupled with a short character limit that prohibits deep discourse and as others have mentioned a lack of comment threads or other tools to organize ideas. The whole thing promote vapid sound bite meme-think, which best fits fanaticism and trolling.
Facebook and YouTube are the other big mass-lobotomizing engines. The mechanism is largely the same-- promoting things that maximize engagement which means the most inflammatory or ridiculous ideas.
He thinks that every idea he has is a good idea, simply because he had it, and therefore his ability to think on his feet and come up with and try new ideas is a virtue; he doesn't understand having to build and maintain something, to provide stability and consistency, because that would mean not using all of his new great ideas.
Unfortunately, all of his ideas sound like he came up with them while sitting around in his mom's basement getting high and saying "wouldn't it be cool if...", so I guess we'll see how this all bears out. My biggest hope is that people see him for who he really is: an insecure and entitled man-child who's never been told no.