Kind of happy about this to be honest. That means it won't be the big spotlight title (or at least get nearly as much attention) at E3 this year. Especially since it's release is 2 1/2 weeks after E3.
2016 - Breath of the Wild
2017 - Super Mario Odyssey
2018 - Smash Bros. Ultimate
With this, I'm gonna guess that their big title they're focusing on for 2019 will be Animal Crossing.
Super Mario Odyssey was not even close to being comparable to BOTW or Ultimate. It literally just had a short but sweat trailer at the end of the direct.
I believe it's a reference to how they decked out their E3 booth for each year, not so much which game was focused on in the actual presentation.