I have no idea what Nintendo will go with, circle pads or control sticks.
The Wii U had circle pads in its dev kits that were eventually changed to control sticks for the final product.
The 3DS uses circle pads, which I guess do the trick, but aren't quite up to snuff. I'm really wondering which angle Nintendo will take. If NX is primarily meant to be portable, they'll succeed the 3DS's design with circle pads. If Nintendo wants to stress the TV functionality for a console-like experience, they may opt for control sticks like with the Wii U's Gamepad.
But, on top of that there's also the consideration for detachable controllers. What if Nintendo really is going for customizable experiences? As in, putting it on the informed customer to buy peripherals for the the input method they prefer? Would Nintendo really go that far as to simplify the base product while complicating the customization aspect?
In a sense, that would provide the best of both worlds, but in practice I'm not yet convinced.