Let me get this out of the way. This is nice. There's nothing reaching too far here. But, it plays with the methods and behaviors many already know, and refines a good bit of what needed to be touched. Impressive, and one can see the work in some of the details.

That said, I don't know if its more of a step back than a half step forward.

I saw/see the N9 as a step towards using the actvity stream as the center of the interaction. Fastlane seems like a step forward in that wise. If this were a full step forward, its leaving the icon-first though, and using the activity stream, gesture-led initiation, and then search/multi-task as that layering-speak UI.... ahhhhh... smiling, excited.

Gosh, I've got to break out my design chops and do something alongside Glacier UI. Seriously, good stuff here. I just see a bit more.

If my attention span can maintain it a bit... I'll go in on this.