if it's fake, the only thing i think would be fake is the design. the concept is probably buttonless but maybe with haptic feedback. there's a possibility that this is nintendo's basic idea down to the scroll shoulder buttons. so maybe if you're a dev and you did want to leak something, you could just make this thing, claim it's the nx even if it's not really the design. nintendo would probably be pissed that the general idea was put out there before they could control the message, especially if it's not representative of the final product.
if it's real then i think it's the handheld and the console's main controller. to that end, i expect a 'wii u pro controller' style nx controller, as well as some sort of add-on for when the nx handheld needs to be a console-style gamepad. to take that concept further, perhaps this oval thing is a sort of gateway to other peripherals, so that when it slots into them. i'm not sure what would be necessary for more than a couple different form factors though.