Less wasted space

I'd like to see a much more "data dense" presentation of the channels and conversations and really everything on the screen. There is far more whitespace than is needed, in my opinion, around everything. For instance, the gaps are massive between each channel in channel list as well as between the app sections in the list on the left and the "gutters" on either side of the chat/discussion within the center content panel of the channels. Compared to Slack, I can see far less on a single screen. This makes it more cumbersome to find things, notice when a channel has new posts, etc.

If not for everyone, then perhaps "modes" where a compact mode is an option like Outlook has.