It's not like we can say we know what every single team at Nintendo is doing and thus there can't be much to announce. A quick glance at their internal and external software teams to look at when they each last released a game shows some rather glaring gaps stretching as far back as 2010.
Those teams are all working on something. Even if there's a 50/50 split between 3DS and Wii U within those projects, that'd still leave plenty to announce.

VGChartz







