That gap between 2018 and 2019 is just going to keep increasing every week. Nintendo didn't really release anything major last year until the end of 2018. This year they are already tracking ahead, and you can bet they are going to have a better release schedule this year.
To the point, they seem to have better mid-tier games in the first half of the year. Yoshi and Fire Emblem should easily beat Kirby and Mario Tennis Aces, though the jury is still out on whether NSMBUD really did all that much compared to DKTF last year.
Add to this a vastly increased 3rd party support (MK11, all those Final Fantasy titles, Super Dragon Ball Heroes, Team Sonic Racing, Crash Team Racing for instance, all with release dates between now and end of June) and the baseline should be quite a bit higher throughout the first half of the year. And that's without any new, additional announcements in Directs or otherwise.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454