Let's not forget that last year their direct around this time was not really as beefy as their direct was in March. I don't necessarily think it will be a mini-direct, however I do think a lot of games that will release in Summer or later will have their release dates revealed in a March direct.
-A few minute spent on the 3DS, includes almost all of the semi-big games that are coming out soon like Mario & Luigi: Bowser's Inside Story, Etrian Odyssey Nexus, and Yokai-Watch 3
-A reminder of Travis Touchdown and New Super Mario Bros. U Deluxe launching on January 11th, with some gameplay showcased for both
-Yoshi's Crafted World gameplay and features talked about, release date revealed, either releasing in late March or early April
-Fire Emblem: Three Houses showcase, somewhat in-depth but not toooooooo long, may or may not get a release date, more so betting on it not getting a release date until a later direct.
-Daemon X Machina showcase, iffy on whether or not it will get a release date
-Piranha Plant gameplay showcase, release date revealed.
-A Wii U Port revealed, coming sometime in Q2 or VERY early Q3
-Town shown off, not too much info but enough to give us a bigger grasp of what the game is about from a general perspective
-A surprise game, something like a 2D Zelda, Pikmin 4, or a new entry in the "Maker" series.
-Some third parties, to be honest I don't really care to speculate on this end
Stuff that won't be shown:
-Luigi's Mansion 3
-Persona Joker Smash DLC
Stuff that i'm iffy on:
-Animal Crossing being shown, I've said before that I'm one of the few people who think a Summer release is entirely possible, but even then I'm not sure this will be shown, because they'll probably have a March direct, an E3 direct, and possibly even a direct just for the game. And if it releases in Q3-Q4, I think this is even less likely.
-Persona Q2 announcement for the West, I think it's possible Nintendo will want to help localize it over here to push hype for the Smash DLC.