Thank you for voicing this concern. There is something satisfying at a deep, almost visceral level about Slack's UI/UX (whatever else you think about it's ability to search/organize information). As someone looking for alternatives, it makes the transition seem very jarring because almost nothing looks as good.

I'm trying to convince a team to go to Zulip but the design adds an extra roadblock which makes it just that much more of an uphill battle.