The current Shuffle has no buttons, the buttons are on the earphone cable. The Nano would get the same cable, so you could operate it without using the touch screen. So the operation for this new square touch screen thing would be exactly the same as for the Shuffle.
Great so you're stuck using Apple's crappy headphones. Or else buy another accessory so you can use your own. I have a newer shuffle and that is my only gripe. Since the controls are now down where the shuffle it is it kind of defeats the purpose of the whole thing (easy access to the controls near your ear while working out etc.). Not to mention the extra accessory takes up amost just as much space as the shuffle.
Honestly earbuds are the dumbest invention. Does anyone seriously use these things? They don't stay in your ears for more than a minute. Forget it if you're actually moving, as in running or some other kind of exercise.