IMO battery is the least of its problems. It's massive, so fits massive batteries.
What I've been wondering about: can you even reach the middle of the rear touch panel when holding the NGP in its default position? I quite like the general idea, but the problem is that you won't know which point on the panel exactly corresponds to which point on the screen, until you touch it, which reduces practical accuracy in games. Unless it has some kind of very accurate proximity sensor to indicate this on the screen.
What I've been wondering about: can you even reach the middle of the rear touch panel when holding the NGP in its default position? I quite like the general idea, but the problem is that you won't know which point on the panel exactly corresponds to which point on the screen, until you touch it, which reduces practical accuracy in games. Unless it has some kind of very accurate proximity sensor to indicate this on the screen.