Currently observers can get cumulative stats in the summary window, like total resources gathered and total units killed. That's great, but it would be nice if they also had access to current stats, like resources (which is available in a tooltip in the top panel if you have a player selected, but that's kind of annoying) or army composition.
This patch replaces the bottom panel with an "observer dashboard" if the observer doesn't have any units selected.
I think having this kind of information would make spectating a more enjoyable experience.