A shadowdropped Direct would both surprise me and also don't surprise me. Why? Because on one hand Nintendo seems to like some "patterns" in their marketing, yet on the other hand they've done even more random things out of the blue.
It's like when you watch the famous Leroy Jenkins video for the first time. You think "looks like this raid group keeps holding to it's strategy and this is going to be an 'expected' video", and then, boom, one player's char stands up, player yells a name in a pretty epic way in the mic and goes YOLO into a room full of enemies.
Only question as of now is: Will Nintendo go LEROOOOOY JENKINS, or not?