People need to think outside the box. There's more to Nintendo Directs than just release dates and new game announcements. We could see a new Smash character. Miyamoto could appear to explain the "secret" hidden in Pikmin 3. We could get an early look at CoroCoro's "scoop of the century," whatever it might be.
Personally I'm excited just on the off chance that they decide to show the new Zelda, since they said they could have shown it at E3 but decided not to. I'm pretty sure we won't see it till after Wind Waker HD is released, though.
More details about 3D World would be welcome, since we still know relatively little about that title. Learning the identity of the as-yet-unknown fourth playable character in Donkey Kong Tropical Freeze is a possibility as well.