I really hope some of the upcoming Switch games incorporate some good multiplayer into it, local multiplayer more specifically. It's disappointing to see that Splatoon may not have (or if it does it probably won't be good) local multiplayer. Even if it was simply just the Salmon Run mode, I would be pretty satisfied.
I don't see Super Mario Odyssey having a co-op mode like 3D World. It doesn't necessarily seem like it would work well, if it is mission based like 64, Sunshine, and Galaxy. HOWEVER, I would love to see some sort of side mode for multiplayer. Not one that's too small but nothing too huge. Like a more expanded version of 64DS's multiplayer or even a 3D version of NSMB's wireless multiplayer!