I find it strange the whole concept of a second movable screen for gaming strange. How exactly do games benefit from this?
If you're aiming for casual gamers, then the second screen will likely add "workload" (for the lack of a better term), as a player will have to share his attention between two screens. Will casual gamers want this?
If you're aiming for the more hardcore gamers, than two screens can decrease immersion, as the player has to stop focusing on the game to twiddle with a touch screen. If the touchscreen also contains some important game functions like inventory as shown in one of the screenshots, then hilarity can ensue when you accidentally swipe the screen while trying to wrangle with that gigantic controller.
I can imagine some multiplayer games benefiting from this, but it simply seems like a gimmick, not an innovation. Sorry Nintendo.