What was Mario Odyssey's best contribution to the ever-evolving design of the mainline series?

[Iztok]

Not sure if this qualifies, but the very best thing Mario Odyssey did was that it's the most like Mario 64 out of all it's sequels.

 

[Timppis]

Reinventing and taking risks.

That's the most important thing.

Boring mechanical stuff: 2D and 3D transitions and costume / coin was great.