I never thought the Wii U would sell like hotcakes, but abysmal flop? Never.
I actually thought the Wii U would rebound with second screen functionality. I still think it can, but it's increasingly unlikely, and would call for more un-Nintendo decisions. Nintendo needs to advertise, but they never do because they think their IP will sell itself.
It doesn't.
I've explained how I would fix the Wii U before, but I'll repeat it.
Step 1: Buy abandoned IP.
Step 2: Write a good script for it and make a new game. Keep production values LOW and style HIGH rather than fighting for photorealistic graphics.
Step 3: Release on your console. Advertise both system and game as a second console (support functions) with a lot of exclusive titles which are highly nostalgic rather than high end graphics.
Step 4: Sell BACK the IP you fixed up for more than you spent on it.
Let's face it: we all know a Nintendo-made Chrono, Legend of Dragoon, or any of a dozen other titles will sell reliably to a limited crowd because Nintendo still more or less translates to quality game (if not console). Not enough to support an AAA game budget, but an AA game? Easy money, especially if these projects were priced at $50 rather than $60. Coincidentally that will also distinguish you from your competition and give your console a reason for existing besides "Touchscreen!"