I was just creating an event and setting some of the people who I know will be attending (the people running it) and I thought it would be amazing to have some kind of quick view in the sidebar of how many people are marked with each status.
Something super simple with just counts, like this:
Guest List: 94
Something like that, just to give a quick view of what numbers could be expected.
I've added in a feature request for this for you.