This whole Nintendo Direct thing two days before the E3 presser seems really odd to me. I can only think of two reasons that they would do this, one bad and one good.
REASON ONE: To set expectations for the press conference. There is no reason to set expectations higher than they already are (that would be insane), so that means this Nintendo Direct is designed to set expectations lower, so that people aren't insanely disappointed after the press conference.
REASON TWO: They want to get the simple stuff out of the way so they don't waste time on it at the press conference. I really hope it is this reason. They only have so much time available for the presser (1 and 1/2 hours usually, if my memory serves me right) and perhaps they tried to fit all the info into that time window, but they just can't do it. So instead they are knocking out some of the simple stuff in this video, and then firing the big guns at the press conference.