We're not sure that the iPod nano always waking to the Now Playing screen, if something is, was the most elegant option. There isn't really any other way Apple could have introduced a quick way to access the Now Playing screen from outside the iPod app, though; and as basically all the new iPod nano can do is play music it's not like you'll be unlocking it for any other reason. It's also possible to set the clock to appear on waking the iPod nano instead, in which case the Now Playing screen is left a tap of the display away.
Navigation may be a little hamstrung by the relatively lower size and resolution of the iPod nano's display than the iPod touch and iPhone, but it doesn't take too long to appreciate that as much as the click wheel was the best input we've ever seen on a portable media player, touch-sensitive controls are blissfully easy, and eminently intuitive.
The iPod nano is just as easy to control as the iPod shuffle, when out jogging, or boating about on a rowing machine. In fact, whereas the scroll wheel could be a little difficult to make fine adjustments on sometimes, the physical volume buttons and lesser need to make small, precise movements to navigate menus mean that the new iPod nano is often easier to use than the old.
Multi-touch is woefully underused throughout the iPod nano's OS. A two finger movement to re-orient the display any which way you chose isn't exactly revelatory; even if it is useful for making the display easy to read when the iPod nano is attached to an arm band. Otherwise there's no multi-finger control at all, which seems silly. Okay, so the Photos application is a bit pointless given the tiny display, but we'd still like to see pinch-to-zoom implemented.
The gap between the iPod nano and iPod touch is wider than ever now. The latter may have gained a camera this generation, but the iPod nano has lost its. Gone, too, is video playback, although that's less lamentable as the screen is far too small to make it a worthwhile experience.