They aren't going to sell it without the gamepad. It would surprise me greatly if they went that route. What they can and should do, however, is to add a Wii-mote to the system and re-market the thing with a much greater emphasis on it being a "Wii 2". The gamepad is not bringing in casual interest at all, so you can drop that from parts of the advertising mix. The most pressing concern is getting the console into homes--after that, then you can go back to advertising casual Wii U games that use the gamepad.
This is what I would do: first, develop casual-focused motion control games and advertise them in family-oriented formats, and second, continue to run gamepad-centric ads in formats that appeal to the core demographic. Having the two different styles in a Zombi U/Fruit Ninja mash-up is a mistake. Get that Wii-mote in there and separate the campaigns. Define your targets and go after them with a tailored approach.
