Mario Kart 8 will be the worst-selling Mario Kart ever. UPDATE: Nope, my prediction was wrong.

[atomicblue]

Wright said:

PAOerfulone said:
At this point, it's safe to say that it'll also outsell Double Dash.
And if it's legs continue to last and be impressive for years even after NX launched, then it could outsell Super Mario Kart on SNES.

Hmmm, who knows. NX might pose a threat to WiiU software's legs.

That really depends on when NX comes out, and what exactly NX turns out to be (since most things are still speculation and rumours).

Most of what I've been seeing seems to be predictions for a Wii U successor in last 2017 (which would make sense given their history). A lot of copies of MK8 can sell in a couple more years, especially since Nintendo haven't done an official price cut yet.