* There's active work on replacing the top-navbar/search area with something nice and clean that displays the stream description, number of subscribers, and other details.
* Our current visual density is really good for power users, but . zooming to 110% makes some people a lot happier and makes Zulip look more modern. We're working on changing the default visual density to look more like that, while leaving the current styling as an option for power users.
* You should try the night theme (in "display settings") -- a lot of folks who are picky about design prefer that one.
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.