Both the 3DS and WiiU while having great features will probable do little to expand the gaming market beyond what the DS and Wii did.
What Nintendo is going to have to do if it wants to expand the gaming market is really on new IP to develop game series that had the same impact on expanding the gaming market that titles such as brain age and Wii fit had.
Nintendo also has to get some of their own core franchises out there showing how great Nintendo games will look in HD. Why did they decide to open with New Super Mario Bros for the WiiU when a Mario Galaxy game would have done a much better job of showing off the WiiU's graphical capacity.
This is the Game of Thrones
Where you either win
or you DIE