I don't think it has to do with OOT3D specifically, it's more like an influx of games starting to come out around the same time.
Here in Japan, there's been a drought concerning 3ds releases. But just the other day I checked Amazon JP and hey at the end of the month the One Piece 3DS game finally comes out along with DOA, then OOT3D next month along with Tales of the Abyss and Biohazard (Resident Evil): The Mercenaries.
There are quite a lot of games coming out for it very soon, which should help to pick up sales (in Japan) as consumers will have a wider variety of software titles to choose from. Being mainly stuck with the launch titles has really hurt sales.
starcraft: "I and every PS3 fanboy alive are waiting for Versus more than FFXIII.
Me since the games were revealed, the fanboys since E3." 
Skeeuk: "playstation 3 is the ultimate in gaming acceleration"
