I have 10-12 recurring team meetings a week (10-15 minute calls to sync with different teams) and a challenge is there is only one meeting owner making managing them a nightmare. I've longed for a "Team Meeting" interface that would allow multiple people to manage a meeting - rescheduling, adding/removing participants, etc. A similar concept to a Email listserv where the email comes from List-Name@Company.Com and there is an web interface and/or understand the standard calendar email commands that could 'Accept/Subscribe', 'Decline/Unsubscribe', 'Propose New Time', etc. Each Meeting could have properties to show who is invited, subscribed (accepted), unsubscribed (declined). When a meeting invite is forwarded, the new invitee would subscribe to the original invite to ensure updates and changes to the meeting are broadcasted to all attendees. This would work for both one time meetings and recurring meetings and with external attendees.
Also, I'm frequently scheduling meetings with people outside my organization and sending my free/busy time isn't the greatest solution. Use Case: I need to schedule a meeting with UserA@Company1.com, UserB@Company1.com, UserG@Company2.com and UserH@Company2.com along with UserM@MyCompany.com and UserN@MyCompany.com.
Google Hangouts are great but not everyone is comfortable with them (yet). An integration with WebEx would be fantastic to handle creating & updating the meeting within WebEx to keep them in sync.