You should be a contender in the circle-jerk...excuse me, Greatest User of 2016 awards. Your consistancy is laudable.

I didn't have any noticeable problems when I played it on Wii U aside from online multiplayer but still good to see

Well, apparently deluxe runs at 60fps in two-player split-screen (wich I think the WiiU version didn't..?), so if you and one of your other friends have a Switch you can have local 4-people multiplayer at 60 fps that way.

Having played over 120 hours of Mario Kart 8 on Wii U, I never found the duplicate frames noticeable, even though I knew they were there thanks to Digital Foundry.

Never noticed it. Never realized the game was 720p on WiiU either because it looks great!

Nice.

Ok, but still, you weren't able to sync up two WiiUs before.:P

Well congratulations Nintendo I guess, I can't see the difference between 59 and 60fps anyway.

The WII U version runs at 59 fps for no appearant reason. On a 60 hz monitor you have to fill that one missing frame with information, so you get a duplicated frame to do so. The picture stays for 2 frames the same and goes to the next.

Frame 1, Frame 2, Frame 3, Frame 3, Frame 4, Frame 5, Frame 6, Frame 6 , Frame 7, Frame 8, Frame 9 and so on, to show you what I mean. That happens to every 59th frame. So what you experience is a microstutter in the game every single second. It's quite noticeable for some people.

You can check it here:

https://www.youtube.com/watch?v=hy2sgmreff8

Run the video at 0.25 speed and you will notice it more clearer when the video seems to have a stutter at some point.

I and several other people notice those things at normal speed and it is really annoying.

I am using G-Sync on my PC for that main reason. Because games on PC can have all kind of frame drops depending on the configuration.

Playing without G-Sync or V-Sync would cause tearing to the screen. That's what Xbox360 and PS3 have and why even the Wii was superior in providing a clean image to your TV than both of those consoles.

V-sync can get rid of tearing, but it creates an input lag and on lower frames you experience stutter when the frames are not equal to the hz.

G-sync sets the hz of the monitor according to the frames and they are always in sync, which avoids stuttering and input lag.

I have a few stuttering and movement removal settings on my TV to make an image look more fluently which is nice in games and crap for everything else. Anyway perhaps I didn't notice it because of that since I usually can distern 60 from 30 fps and a fluent 60fps to an unstable 60fps.