These are the 2 things that I would've liked to see in the new Mario kart

1. I wish they would've kept the old battle mode from 8 along with the new battle mode, as it would've made the game feel more "complete" to me and I enjoyed that battle mode to.

2. If they would've added new tracks to this release, though I'm sure they're working on DLC to milk even more money out of us lol.

I just want to see it release :p

I remember playing MK DS and always wished for a console-level mario kart game. Now our dreams have come true

Sounds crazy and would never happend due to technical limitations(data transfer):
-Download Play.

Download Play and Free online would be great

Fun fact: the very first game I ever played online was Mario Kart DS.

I'd like to see that decal creator return. They made some awesome art back then.

A Splatoon course in race mode pleeeeease Nintendo

The battle mode on this game is going to be an absolute smash hit. Zelda BOTWhat?

They've fixed 2 of my biggest concerns already.

1. Frame rate issue 59 fps which led to "stuttering". Actually one frame was displayed twice due to vsync 60.
Now it fully runs on 60 fps.
2. You can now chance your character and vehicle while being in the online lobby. On Wii and WII U you had do reconnect to the online session in order to do it.

Download play worked for Mario Kart 7 on the 3ds. You could only choose a shy guy and standard kart, though. 

I don't think they will feature this on the Switch, due to higher amount of data. But I hope I am wrong.

Better than the DS version that limited you to Shyguy and only a few stages though :p

It's unlikely, but would be a nice addition