Remember when Miyamoto announced that he was working on a new IP? What could it be that he is working on?
It is most likely an FPS. Why? Miyamoto said that he wanted to experiment with the FPS genre back in 2012. The other reason is that Iwata said that he does not understand the Western audience. He must be doing something to turn the Wii U around. Nintendo should know that this E3 will mean Do or Die. They will need to unload all their games on the audience and must do a conference.
Imagine a Nintendo FPS that has game modes similar to CoD, environmental actions and dynamic maps like BF, vehicles and weopons similar to those in HALO, and a Nintendo campaign that has you play through events that are similar to events in specific Nintendo games. This will be that one game that will make everyone sit and be like, "Da Fuq!" The internet will explode, fanboys will cry, and Wii U owners will be excited to a point where they may S**t themselves. E3 2014 will be the Wii U's Judgement day.
EDIT: I forgot to mention that Nintendo filed a trademark for S.T.E.A.M: Strike Team Eliminating the Alien Menace. Sounds like a FPS to me. I dont care if its an alien shooter as long as it include online multiplayer and some features I said like game modes vehicles and environment interactions.