I think Wii U won't get better 3rd party sales because everybody can get even better version from PS4/Xbone or from PC for even cheap. There is nothing from Wii U to separate from other version and also its inferior version of PS4/Xbone/PC and little better than PS3/360. Nintendo should have used architecture similar to PS4/Xbone if they wanted good 3rd party support.
GAMING is not about spending hours to pass/waste our time just for fun,
its a Feeling/Experience about a VIRTUAL WORLD we can never be in real, and realizing some of our dreams (also creating new ones).
So, Feel Emotions, Experience Adventure/Action, Challenge Game, Solve puzzles and Have fun.
PlayStation is about all-round "New experiences" using new IP's to provide great diversity for everyone.
Xbox is always about Online and Shooting.
Nintendo is always about Fun games and milking IP's.