People have reported <5W on netbooks for a while.
New ITX Atom ... stick it into any regular ITX case with a good 120mm fan to keep it real cool. Since the power input is on the board directly, no need for a PICO, one less part. A good 24W brick and you could probably be on par with 11-12W consistently.
Last year's board with a decent brick with a higher rating could get you <10W consistently. And you wouldn't need a fan or to keep it cool.
... to replace 5 old desktop terminals they have, in an effort to make it easier to work on their computers, and cheaper for them to operate. NUCs are low power, but not as low power as the new Atoms are. If only the Atoms could do HD on their own, things could probably change (Haswell?) Considering my dual atom HP netbook isn't really that much of a slouch for basic use with an SSD, the new ones can only be faster and more efficient.
The 2012 Atoms weren't much of an improvement and in some way a step back. The details depend on what parts you're comparing exactly of course but the CPU you mentionned isn't the fastest so it might not be significantly better than your netbook.
There are two main issues with 2012 Atoms: the graphics driver and single-threaded perfomance. They're not necessarily deal-breakers but they're real issues depending on what these computers are inteneded to do.
I don't think HD as such would be a problem (older Atoms could play HD) but I would of course not recommend Atoms anymore for that considering AMD's offerings.
The next gen of Atoms which is supposed to improve substantially on these issues is called Silvermont. It's due late this year though you might have to wait (a lot) more for boards to appear in retail channels.