The second screen is just another option to interact with the software, nothing less, nothing more.
It´s not mandatory to use it, see the example of games like Need For Speed Most Wanted and Injustice: they make minimal use of the second screen but still are as playable as their counterpart on PS3 and Xbox360.
Nintendo tried to sell the idea of the touchscreen being a differential, but it seems that they notice what really stands out in a console is its library of games. So much that they have a good lineup for the WiiU this last quarter.
The same can be said about Kinect on the XboxOne: MS is not promoting the new console based on it, at the contrary that everyone believed one year ago.








