In addition to being a separate game display, the portable controller screen is also incorporated into traditional play. (canadianbusiness.com)
Sending some of this to a second controller screen will alleviate some of this. (joystikrevolution.com)
Considering the system actually being able to handle this kind of game, and the possibilities of the Wii U controller screen playing a part in the action, they could make this work pretty well. (snackbar-games.com)