Differences between creating an event via e-mail vs calendar
I noticed some differences when creating an event via e-mail instead of creating it in the calendar. I hope they could be considered enhancement requests for your next round of development.
1) When you create an event via e-mail and set it for a future start date, the end date remains as today. Ex: In the video below, you'll see me attempt to create an event for next Friday, 06/25/2014. When I change the start date, the end date should naturally update to 06/25/2014 as well, but it remains today. Your calendar app automatically updates the end date to the start date that the user entered.
2) Similarly for start time, when I set the start time past the existing end time, it should update the end time. Ex: In the video, I change the time to 6pm, but the end time remains 5pm. In your calendar app, it would have automatically changed the end time to 6:30pm when I set the start time to 6pm.
Video:
http://screencast-o-matic.com/watch/c2iFYunH7U
Both of these issues cause the end user to do unnecessary correction work. Your calendar app is programmed to avoid these issues, so hopefully you can mimic the behavior of the calendar app when creating an event inside of mail.