Ugh.
I really wanted Nintendo to make a main Mario Kart game for the switch. Unless this is like Animal Crossing Pocket Camp were it will have a lot of use in a future switch game, then I am not happy about this. They likely aren't making a main Switch Mario Kart if this is a big game, and considering they have announced it a year in advance, then it may very well be.
Nevertheless, if it is a main game, then here are my retro track predictions.-
Shell Cup-
1. DS Figure 8 Circuit
2. SNES Choco Island 1
3. Wii U Sunshine Airport
4. Wii Toad's Factory
Banana Cup-
1. SNES Vanilla Lake 2
2. N64 Wario Stadium
3. Wii U Super Bell Subway
4. GBA Sunset Wilds
Leaf Cup-
1. GBA Riverside Park
2. 3DS Shy Guy Bazaar
3. Wii DK Summit
4. GCN Bowser's Castle
Lightning Cup-
1. Wii Shroom Ridge
2. Wii U Cloudtop Cruise
3. 3DS Maka Wuhu
4. GBA Rainbow Road