Here's what I think Nintendo digital event/direct will definitely cover:
3 min introduction
3 minute Mario Maker
3 minute Yoshi Woolly World
3 mins StarFox trailer
3 mins Starfox info
3 mins indie game Wii U and 3DS
2 min Smash Bros. Lucas dlc and smash ballot winner annoucement
3 min update on Smash Bros & Splatoon dlc
5 mins of Xenoblade X (new trailer + info)
3 min Devil Third trailer
5 min Amiibo title
2 mins full of random clips/sketches used for transition (like those robot chicken sketches last year)
That's 38 minutes so far. 2013 and 2014 directs or digital event were around 45 minutes and I believe this year will be too. So that gives them 7 - 10 minutes to show something new for Wii U and 3DS games since QoL and smartphone won't be discussed this year.
On the plus side, I think there will be more games shown on the media press that will be skipped on the digital event. I predict Nintendo will be more focused on hyping 2015 titles at the digital event.