Gamepad is a red herring, Software is overestimated, Nintendo needs to address 2 major problems with the Wii U: Lack of Developer Support (Which is just lack of developer interest) and lack of consumer interest.
While strong software (specifically 1st party) can attract consumers and larger base is more attractive to consumers, strong software can also be toxic to 3rd Parties i.e more competition less profits. If Nintendo is arguably the best software developer, what developer would be mad enough to challenge them on their own court.
Thus the need to address consumers with more than just software and since the new consoles are selling more at higher price, price isn't the issue with demand. What else do the PS4/XB1 have? More Hype/Media attention, better 3rd party relations, more extensive network support.
Hype/Media can be addressed with Marketing, 3rd party relations are damaged by Wii U design but can be made up with User Base increase, advertising, and Online Network expansion. The Network can be improved with Money, which Nintendo apparently is sitting on.
In this day and age, with the Internet, ignorance is a choice! And they're still choosing Ignorance! - Dr. Filthy Frank
