A good portion of Google I/O was spent, naturally, on the design of applications, and Google apparently gave a little sneak peek at what probably is an upcoming redesign of the Gmail app. As evident in the Structure in Android App Design session, Jens Nagel shows off a redesign navigation drawer that combines several views into a single drawer-style UI.
As the slide above shows, there are different layers to the views, collapsed by default. And most important is that you can get to this drawer from anywhere in the app, which is what lets them get rid of that lower Action Bar. (It's almost in the same vein as the BlackBerry Hub in BB10, just at an application level instead of at the homescreen level.) It should also mean a much faster switch between labels, long a sore spot for some of us here.
If we had to guess, we'd expect to see an updated Gmail app roll out with the expected Android 4.3 update, whenever that's available.