I had two suggestions:

1. Many of my contacts have birthdays stored in their contact
information. Integration to put this information on my Google Calendar
easily would be appreciated, so I don't have to duplicate the data and
maintain it twice.
2. Some events feature travel, such as flights, etc... being able to
specific multiple locations within one event would be useful in a lot
of scenarios. Being able to attach time frames to these events would
be even more useful.