Nintendo hopes that the Wii U's GamePad would be the preferred controller input for core gamers…specifically, Call of Duty.
In an interview with GameSpot, marketing executive Scott Moffitt hopes the Wii U's tablet controller will give people a way to "reimagine" games on the Wii U. He even gives an example on how Call of Duty can be the "preferred" method when using the GamePad.
Do we want to reach out to the core audience? Absolutely. They're very much part of our audience and the group of consumers we hope will find the way you can reimagine games on the Wii U. The Wii U could become the preferred way to play those games for some of the core gamers. You can imagine how a game like Call of Duty would work on the Wii U–the GamePad will allow you to declutter the TV and pull gaming items like maps down and not interrupt your interaction and enjoy the cinematic quality of the game on the TV. That's one application that could be exciting and could enhance gameplay for a core gamer.