I honestly have trouble believing Miitopia is a 2016 title.
On the other hand, Momotaro Dentetsu 2017 did look like it was pretty much completed when they showed it (and given the usual deadlines for retail titles, it most likely was). Wouldn't be surprised if they didn't show anything until next month, to be honest (still think we should hear something this month, though).
I don't think Ninty had the luxury of having totally 0 game on December though. I am sure Miitopia is going to be their big games for holiday there together with Pokemon.^_^