We were mostly thinking that the stuff that came before was hard to use and had a steep learning curve. And being decentralized, it was way harder to iterate on than a wholly-owned service.
Twitter (the technology) is okay. It turns out people work poorly when you put them all in the same room and let them shout at each other.
Yours is a point that bears repeating: Twitter is fine (not that I use it).
What's not fine is people: they prefer to be in a place in which they can yell at each other about how much more virtuous they are than their villains.
It feels good to vilify somebody. It feels good to verbally punch a nazi.
I don't know what we can replace Twitter with that will make people less interested in public displays of virtue as they stand up to their ideological enemies.
One option is the thing we used to have: private displays of virtue in distributed systems.
When Reddit is hosting racists, it's easy to blame Reddit (and, more specifically, easy to put pressure on them to deny those users a forum on Reddit's servers). When such content is on a distributed, federated system, it's up to individual service providers how much of a tolerance they'll have for speech others consider completely unacceptable. Some will choose not to host it, some will perhaps choose to host it (and others can choose to peer with them or not)... But in general, there will be more variety of opinions represented in what is "acceptable behavior" when there are many distributed systems instead of a few centralized ones. This does, of course, increase the complexity of accessing them...
... honestly, this probably mirrors societal development as a whole. In a town of frontiersmen, you barely have enough time to worry about what goes on in your neighbor's house. In a city, where you can hear your neighbor through the walls (and have deeply-intertwined interdependency networks through which pressure can be applied), you both have more reason to care and more tools to pressure someone to conform.
... all of that having been said, to take a step back from the mechanical and consider the philosophical, I'm not sure it's an inherently virtuous thing that my frontier neighbor could be out there doing Texas Chainsaw Massacre stuff and there's little structural pressure that can be applied to get him to cut it out...
Twitter (the technology) is okay. It turns out people work poorly when you put them all in the same room and let them shout at each other.