With the NX on its way, we all know that a Mario Kart is also on its way. Mario Kart Wii was the best-selling racing game in history, as well as the best-selling Wii game (aside from Wii Sports which doesn't count because it was bundled with the system).
What they showed in the NX reveal trailer looked like MK8 again with King Boo added as an extra character.
Let's ignore that.
Let's assume they're making an entirely new Mario Kart game. It can be on the same engine if they'd like, but it'll have to have new courses, new characters, etc.
So let's first talk about the "retro" cups, which have been a mainstay since DS. MK8 started reusing tracks that had already been used previously (SNES Rainbow Road, Baby Park), so let's add all those back to the mix.
Let's also remember the anti-gravity and underwater aspects of MK8 while we're considering courses.
I'm going to ignore all MK8 courses for the purpose of this list, since I'm assuming it will be on the same engine.
Here's my list:
SHELL CUP:
Luigi Circuit (GC)
Daisy Hills (3DS)
Choco Mountain (N64)
Toad's Factory (Wii)
BANANA CUP:
Wuhu Loop (3DS)
Mario Circuit (Wii)
Shroom Ridge (DS)
Sunset Wilds (GBA)
LEAF CUP:
Kalimari Desert (N64)
Vanilla Lake 2 (SNES)
Maple Treeway (Wii)
Waluigi Pinball (DS)
LIGHTNING CUP:
Broken Pier (GBA)
Wario Colosseum (GC)
Bowser Castle 3 (SNES)
Rainbow Road (GC)
As far as characters go, take the vanilla MK8 roster and add:
RETURNING:
Dry Bones
Diddy Kong
Funky Kong
Bowser Jr.
King Boo
Petey Piranha
Wiggler
NEW:
Dixie Kong
Kamek
Spike
Monty Mole
King Bob-Omb
Pianta
Nabbit
Professor E. Gadd
Remove all babies, thanks