I was thinking of writing up an Xbox E3 Wishlist and Predictions article (perhaps I still will). I'd say the obvious are more gameplay from announced yet unreleased titles (e.g. Scalebound, Crackdown, ReCore, Halo Wars 2, etc.). Also, unless they need to backtrack, some form of Crackdown 3 multiplayer gameplay, likely just a beta, should be available this summer, so I'd expect to hear more on that.
Rumors are rampant of the Xbox One Slim and/or Xbox One.5, I expect there's some truth to the rumors, and that we'll get more information.
I'm hoping for a new Banjo title, namely a more conventional 3D platform/advaneture.
I'm also hoping, somewhat baselessly expecting the announcement of backwards compatibility for original Xbox games ("first Xbox games playable on Xbox One" is only one of the potentially sexy yet confusing taglines for this announcement). Less likely would be older PC games becoming playable on Xbox One. With the Windows aspect of the console, I'd love to see this become a reality.
Those are the things that immediately come to mind. As I may write an article largely reusing my comment, let's all keep this on the low and pretend to be surprised by what I write...if I write it...you get the point.