That said, I think any game that sells over a million on Wii U would have to be considered a massive success. There won't be too many in the consoles lifetime.
Every mainline console DK in the past 20 years has sold over 5 million except for DKC 3(it released over a year after next gen started). Thats on SNES, N64 and Wii so install base doesnt really affect this series sales. Also Nintendo games have tremendous legs and this game will likely still be selling decently 3-4 years from now.
Previous games in the series werent affected by other platfformers, SNES, N64 and Wii were all filled with that genre.
And in no way shape of form can u call the 3DS port a flop. It is currently at 650k, will moat definitely be over 1 million by the end of the year and very possible to sell 1.5-2 million lifetime. Not alot of ports can do that.
Even if Wii U ends up with lifetime sales of 15 million, this game will sell 2-3 million.
When the herd loses its way, the shepard must kill the bull that leads them astray.