I guess/hope you are talking about enabling Arbitrary Sized Ads (non standard ads) to all publishers.
No, I don't think AdSense is ready to release anything. I think they're just going to give their permission to using a PHP if/then situation to serve ads based on the viewport, as long as you don't alter the code.
is it really a case of "light touch"
I'm not sure what that means exactly. It did force me to think hard about what I put where, because I want the most important stuff above the fold, and the fold changes depending on the viewport.
In my case, most users don't want to roam the site like they might on a desktop, they're looking for specific information, probably while they're out and about, and that's it (although given how the number of pages per visit is going way up, I might be wrong about that)
I still have tweaking to do as far as font sizes, and getting an image header to work okay and look right in all sizes is a serious struggle for graphically challenged people like myself, but at least the *site* part works.