It's such a great system, I still have a PS4 and Xbox but they don't hardly get used compared to my Switch, the portability factor makes such a difference as it's so immediate.
I had Mario Kart on the Wii U but don't regret buying it for the Switch as such a great game.
I hope you enjoy Mario Odyssey, I liked it but I don't think it was the game-changer some made it out to be, just a solid 3D Mario for me. Personally I think Mario 3D World on the Wii U is the better game, doubt many would agree as more linear but the style, music, clever levels and multiplayer put it in front. I really hope they release it for Switch (maybe at a cheaper price point) so more people can experience it.
I'm still addicted to Zelda, is possibly my best game ever, I'm at 135 hours and still have so much to do but I just love being in that world, I just wish Nintendo would make more DLC or an expansion.