I've spent a bit of time last year trying to convey my product instincts to the Zulip team and mostly stopped because I felt like they didn't care enough / weren't moving very fast. The basic problem is that the mobile app is, like it or not, the way most people will use the product, and it needs to be designed by an opinionated person who actually will say no to things.

In my view, the home page should be just like a proper messaging app: show every recent thread ("topic" in Zulip nomenclature) that I'm involved in, across all my channels, with unread ones indicated using a 'dot'. Or, if you really want to be like Slack, just copy Slack more directly. In either case, the other views (Inbox, Combined Feed, DMs, etc) should be under menus, not primary actions.

The other thing is that it's often hard to figure out how to reply to a topic. In the Combined Feed, which is my preferred view for consuming updates, the UX for replying sucks -- first you have to figure out to tap the headers; and even then, you can accidentally tap into a channel instead of a topic. It's extremely non obvious when you've done this and constantly causes people to reply in the wrong topic.

I vibecoded some improved Inbox UX using Claude Code and I think it would be a big step up, but it's hard to know what the steps would be to get it shipped, since I don't have time to spin up properly on the codebase and I doubt my changes are acceptable as-is. If Zulip team wants them I'd happily share though.