The problem with lots of mock-ups here is that they are trying to transfer Wii U experience into this controller. On of the reasons why Nintendo, making dual-screen games since early 2000s, failed to make universally appealing dual-screen experiences for Wii U, is because the screen of Wii U GamePad was too big to just throw a bunch of icons and HUD elements on it, so developers (both first- and third-party) have to develop quite complicated schemes if they want to make use of GamePad.
Nintendo 3DS touch screen is just too small to clutter it with maps, icons, sliders etc., so it's often used just for a bunch of buttons and UI elements (and it works!). When someone tries to make minimalistic UI for Wii U GamePad's screen, it looks awful and impractical and is ridiculed a lot (Mario Kart 8's horn).
This controller is obviously smaller that the Wii U GamePad. Even if the screen is roughly the same size, its main active zone is obviously smaller, so let's imagine developers are translating laconic Nintendo 3DS touch screen experiences rather than grotesque Wii U ones. Basically, let's make mock-ups using screenshots and footage from 3DS games.
Here's my quick and dirty translation of Super Mario 3D Land touch screen UI to the supposed NX controller: