I still don't entirely get some of the arguments with the ship has sailed, etc. I do agree that their first year's performance was pretty miserable. However, Nintendo actually had unprecedented sales for certain series (and their console) last generation. Doesn't that at least give some hope that they introduced Mario, etc. to a huge populace they didn't before, and that perhaps they impressed some portion of them?
Let's take a series like Mario Kart. If out of the 35 million sales, if you've impressed even 5% of those owners enough to buy the game's successor along with its successor's console, you would technically get 1,750,000 sales. Lower that to 1% and you still have 350,000 sales. It's at least a bunch larger base to tap into compared to what Nintendo had in the N64/GameCube days.
I still think that the biggest strength of the Wii U ironically is that basically no one knows about it. As such, there may be a chance that it can be made appealing to this audience now that it has games. Honestly at least to me the current-gen consoles have much more appealing libraries than any of the next-gen consoles will at this point, but at least of the PS4/XB1/Wii U, the Wii U at least carves out its own types of games. I'm still not sure how many people are actually going to buy the cross-gen games on the next-gen consoles. Sure if you have a PS4/XB1, you'll buy it there (assuming the price is about the same), but if you don't, I see most people buying Watch Dogs, etc. on the 360/PS3/PC.