On Tuesday (April 19 2016) the COMMON user group hosted a presentation given by Steve Will, chief architect of the IBM i, and COMMON board member Peter Massiello on the new release 7.3. Fortunately COMMON has uploaded it to their website, and made it available to the general public here.
The presentation is a little over an hour, and covers all of the major features in the new release. It is definitely recommended viewing for everyone who is interested in the IBM i and its future.
May 20, 2016: Link updated as the video was moved to a different location on the Common website.