I think that any kind of chat is as distracting as you let it be, I would not blame that to Slack. However, I totally agree your UI points however for me it app

I think that any kind of chat is as distracting as you let it be, I would not blame that to Slack. However, I totally agree your UI points however for me it applies to Slack overall. Having a thread open on one side, middle being a war between people who use threads to reply and the others using mentions to reply and the left sidebar with bots/apps/direct messages/channels/starred things/all unreads is getting a bit populated too.