I don't know about the Switch version, but on 3DS, the Plucky Pass Beginnings glitch has been patched. And on Mushroom Mesa, the touch platforms at the back of the stage are at different heights compared to the Wii U. The Switch version will probably have the same differences, and both will probably more. I won't know for sure until I get the game tomorrow.

However, with all of this, it would make sense to create a new leaderboard with separations between the two systems. Especially because playing in handheld mode/3DS will be drastically different from playing in tabletop/TV mode, due to the motion controls allowing access to platform manipulation, while also being able to move the camera or dash.

And lastly about the slowness, in my experience, it doesn't seem slower than other versions when playing them. I'm able to match Wii U times after all. However, I do completely understand that this version runs at 30 FPS.

UPDATE: I didn't realize you can sprint with Y, B, A, and ZR...So in fact in some cases, it would be harder on Switch, as according to reviews, you press ZR to trigger touch platforms.