#1 Breath of the Wild
#2 Super Mario Odyssey
#3 Mario Kart 8 Deluxe
#4 Splatoon 2
I'd rank Mario Kart 8 and Splatoon for Wii U higher than Mario Odyssey, but the Switch versions don't bring a lot of new stuff, so I didn't really play them much yet.
Mario + Rabbids looks pretty fun, I might buy it eventually. I don't know about Xenoblade though, it doesn't really look like my type of game.