Sometimes you get in a situation where the only choice is a win-lose; Nintendo is in that situation. The Wii has been out for almost 5 years and it has just started to die. It is not dying because people hate it, its dying because everyone already owns one. This is why Nintendo needs to release its new console soon. Nintendo could lose even the people who only buy the new Mario game or the new Wii Insert Noun Here game (aka the non-gamers whose first console they really played was the Wii) if they tried to hold out for the rumored 2014 release for the new Xbox and PlayStation. If they don't get something new for all the moms to buy tier kids, Nintendo might find themselves in third place since developers are just starting to unlock the full potential of the 360 and PS3. On the other hand, the thing that will kill the the Wii U is that it is not next-gen. The reason the 360 could come out a year before Sony's and Nintendo's new consoles was because it ushered in a new era of tech; the Wii U is not doing so. They say it is as powerful as a PS3, key words: AS POWERFUL. What happens if a new Xbox and PlayStation does come out two years later in 2014 with more power and already established motion control gimmicks? Most likely, developers will stop using last gen tech after about a year and move on to the new thing, just like this generation (remember Marvel Ultimate Alliance on Xbox 1?). Sure it will have its dance games and mini game collections, but if Kinect or Move pick up steam even those game might jump ship.
These are just my thoughts on the Wii U situation. It seems to me that this is just a stop-gap system that won't hold the moms and kids attention as long as the Wii did. I predict, if indeed a new console generation starts in 2014, that will have a new console in 2016 WITHOUT the Wii branding.
Also, I don't mean to diss the Wii or Wii U by saying it won't hold the moms and kids attention as long, or any similar things, I am just saying that is what Nintendo seems to be aiming for with the Wii brand. For gods sake, they called it Wii because they they wanted people to play together and to get everyone involved.