This is completely my opinion, but if I would make Slack 2.0 or Discord 2.0 for that matter, I would add the option for no hidden or locked channels. all is free for everyone. Maybe even no dms. I would make thread autocreate a new temporary channel that can be archived after some days inactivity. Channels in my mind are hubs. If a conversation starts, all is good. if a second one starts, it's time for a temporary split. Finally, better notifications. I know the Slack team has done a very good job with them, but they need moooore work. That's one thing I don't know exactly how it could be improved. I just know that it can and should be improved.