I'd like to think that Tilmen has some inside info and can be trusted with this stuff. With that said, still consider this 100% rumor.

RUMOR!!! A Nintendo Action Game is in development for #WiiU. - not a big but Known franchise - maybe eShop only - reveal & release soon

— NiNTENDOMiNATiON (@TiLMEN) March 15, 2014