Holding that "leak" version of the controller looks like it would be pretty hard without the grips shown in the patent document.
Really, when you think about it. When's the last time Nintendo made a controller that didn't have some means of gripping it? The Wii U Gamepad's grip is on the back, but works because there's plenty of room to grip it. The "regular controllers since the N64 all have a grip on them (or should I say VB). Even the Wii remotes are great for individual gripping. The patent for the supposed NX controller even has grips. Where exactly is it that you grip on this prototype? Have other "leaked" prototypes from previous system had missing grips?
The "base" of this prototype is so simplistic that I could imagine it being made with a 3D-printer and apply a decal to it. Now, what about those analog sticks? Is it just me, or do those really not look like they'd work with so little area to tilt them (if the tilt-able area is hidden underneath the button-like cap)? Now how about what's supposedly the bottom of the controller. I believe that's a camera, which might work as Nintendo's DSi had one on the hinge between the two screens. But what is that other black rectangular part? It almost looks like what's you'd find on the tip of a Wii remote or the top of the Gamepad next to the audio port, used for IR signals. If that is what it is, then why is it on the bottom?
Speakers and microphone hole on the bottom. Look very similar to the Wii U Gamepad's versions. However, having seen a teardown of the Gamepad and looking at the internals, the speakers on it are decently big and round, which makes me believe if this supposed "prototype" is similar in nature, then it can't possibly fit in that area, even if it was right up against the edge.