Well, we know about holidays.
Anecdotally, I don't expect giant WiiU sales until there is a break from school/study. Like summer break, Obon or similar. A big audience this appeals to (kids) are not in to position to blow 30,000yen on a system. And their parents will either need a gift occasion or an opportunity to give it as a reward (for example: good test scores) The kids I know (my students) who have a WiiU are planning to get the game but haven't talked to anyone who bought a Wii U this week.
What might be more important is the growing mindshare. People are talking about Nintendo Wii U again. I really hadn't heard people talking about it since shortly after the holidays. It might not be yet be enough to get people to pull the trigger for what
is essentially a $350+ (with Mario Kart) purchase. But people are saying they want to play Mario Kart 8. They are talking about the ad on TV. And they are at least keeping an open mind to the possibility of owning a Wii U (If there are other games they want or a price drop, or whatever else is still keeping them back).
Unfortunately unless Nintendo builds on this "positive Nintendo vibe" going around now, by the time people traditionally are in a position to buy a system (holiday or long vacation) the excitement may dissipate. People are fickle. And the Smartphone is "good enough" for most.
Take that all with a grain of salt. But it is nice to hear kids talking about something that isn't PuzzDora or something of that ilk.