This seems to fall in line with Google's Android strategy of moving functionality out of the core OS and into Apps. This makes updates easier and faster because users only have to download the new version of the app and not update the OS.
While the cynic in me is deathly afraid of Google having complete control over my digital interactions, I find myself in favor of a Google-controlled experience. Google Now is making contextual computing possible in a way that no other company is remotely capable of bringing to the market. For the time being, I invite Google to control Android this way.
that's always a bad move. and they've been doing it a lot lately.
They COULD contribute their changes to AOSP, AND include them in a separate app, but choose not to.
Which ironically is something you now don't get if you bought a Galaxy Nexus 18 months ago.