Associate an activity to multiple people
Provide the ability to 'Tag' an entire team on an Activity, not just users individually.
Provide the ability to associate a new Activity on a Deal with more than just one person (for example, being able to associate three people to an Activity if that Activity is tracking a meeting I had with three People).
Annie Knipe commented
Add the ability to multi-select records to add to one event type.
IE: Meeting with 4 people, create one event and link it across the 4 invitees.