Attendees and organizers who have a series of meetings should be able to add agenda items to a specific instance of the meeting. Currently, I have a series of 1:1s (some of which I organized and some of which I'm an attendee). Most people in our company track the agenda items for those meetings in Google docs because there's not easy way to add agenda items to a meeting without resending the entire invitation. Many meetings scheduled in a series don't have a fixed agenda for each meeting; rather, each meeting needs its own, flexible agenda. Ideally, this agenda would be a collaborative, shared agenda that didn't require resending the invitation each time someone added something to the agenda. If I add my own agenda to the meeting where I'm an attendee I receive a warning that my notes will be deleted if the organizer sends an update to the meeting.