I think if we're getting a Direct on the 23rd like the rumors have said we should hear about it by tomorrow at the latest (unless it's a surprise one). Since Iwata seemed to be heavily in-charge of how the Directs worked the unsaid rules about how they worked (how far in advanced they're announced, when they usually are, etc) could be completely different now.
That being said, we usually get one by this time every year, and since we haven't had anything like it since E3, now would be a perfect time (they could go over Splatoon, Twilight Princess HD, Mario Tennis, Paper Jam, maybe some Smash stuff, and one or two other smaller things).