The UI of the system monitor extension (part of gnome-shell-extensions) could do with improvement. It currently looks like this:

The UI doesn't look great. Also, people probably want to be able to see resource usage without having to open the calendar.

It might be best to swap out the extension entirely, either for a new one, or for another extension which is maintained upstream. I've come up with some design ideas in case we want to roll our own.