Mario Kart Wii gets called 'Mario Bike Wii' or 'Funky Bike Wii' or Daisy Bike Wii due to rampant use of bikes or speed-boosting characters.
Mario Kart 8 sometimes gets called Mario Kart Zero, due to the anti-gravity being like that of F-Zero.
Some people were also calling it Mario Riders Zero Gravity when it was released, due to the gravity gimmicks, though they're hardly the same.
I Knew It: Many had predicted N64 Rainbow Road would return for Mario Kart 8.
Killer App: 8 is shaping up to be one for the Wii U.
The Other Darrin: In Mario Kart 7, instead of Mercedes Rose reprising her role, Rosalina is instead voiced by Kerri Kane. No explanation is given for this change. In 8, she is voiced by Laura Fay Smith, her actress from Super Mario 3D World.