Mario Kart 8 helps Nintendo’s Wii U turn a corner, lifting console sales more than Titanfall or Second Son - MK8 tops 2 million....

[phaedruss]

The problem is that the Wii U will not have as many good releases as consistently as the PS4 or Xbox one. In fact, Watch Dogs is the only major third party release coming up that I can think of, and that doesn't even seem certain at this point.