WiiU is selling at half the rate of the Dreamcast. It's dead. No amount of software will make it profitable for Nintendo. They could have Kart, Smash, Zelda, and Metroid all this year and it would only give the system a minor uptick in sales.
They aren't going to sit on it for 3 more years I promise you because it is killing their bottom line.
They always launch consoles in the holidays.
It isn't happening this holiday and if they aren't going to sit on it for 3 more years they then it must be launching next holiday.
Couple that with the rumors we heard about new hardware from IGN, Videogamer, etc...
Yeah, WiiU is done and its successor is on the way sooner than you think. The idea that the two consoles might share games isn't out there as it has happened before with Twilight Princess.
So yeah, I do think that this is what is going to happen.
I think Nintendo's E3 is going to be rather mundane when it comes to new unknown content for the WiiU. I really hope I'm wrong but I don't think so.
3DS will probably have more new stuff to announce by a healthy margin.