My favorite so far is Mario Kart 7, for 3DS.

I don't have a Switch, so I haven't played Mario Kart 8 yet.

8 and DD is better than all others. We had some features very interesting in some games, like missions in DS, plenty of ghosts at same time on 3DS time trial
Well, if Id go with a next tradicional MK (supposing for instance is not VR related), Id go in improving the DD and MK8 and with the best mechanics of MK together.
-More dynamic stages: imagine stages rotating, changing the antigravity zones every lap, transparent floor where you see the driver that took other direction below you, tubes, maleable stages, moving floor, etc.
- Special items for each character, like on DD (baby mario with chain chomp, bowser with huge spiky shell, peach with protection), etc, also, let us change the items like in DD
- Time trials with lots of ghosts like in 3DS. (the only game I enjoyed playing time trials for hours)
- Missions like in DS, with improvements (online mode too?)
-All battle options like in DD and 8DX

MK8 is easily the best for me. By far.
I didnt care for DD's gimmick
I loved 64 and SMK back in the day, tho I dont feel they aged very well.
I wasnt particularly crazy for 7 or Wii
Havent played super circuit.

MK8 for sure. Once I get DX, it would go to MK8DX

The most polish and refined version of them all

2nd would go to either Double Dash or DS

I never played the portable version in the fear the joystick would fall off lol. As many had issues. Did you run into any issues like that?

The DS only has a d-pad so it won't fall off :p

But for the 3DS, I never had that issue, though I didn't play it as much as I did with MKDS

Fondest memories: Super Mario Kart & Mario Kart 64
Most played: Mario Kart Wii
Best game: Mario Kart 8

Ah yes i assumed yo mean 3DS.  3DS scared me after playing resident evil with the amount of quick joystick movements needed to kill enemies haha

Think it's more of an issue with games like Smash 3DS, but since I usually play RPGs or more relaxed games on my 3DS, my circle pad has yet to break, which I am grateful for