cord- well the main point you bring up is that top brands get larger pushes during the holiday seasons. Wii was struggling this time last year in Japan as well but it still got sizable increases during the holiday season. Same with DS who was also struggling (even without the need for DSi). So I do think that is one factor that needs to be brought it.
But also need to point out that PS3 has made quite a name for itself in Japan over the past month or 2 which really could mean it's taken a lot of that top brand away from Wii. Of course we made similar arguments last year and those turned out false as well.
What I just think needs to be stated is that Wii and PS3 have essentially been close since the end of holiday season in Japan from last year and it looks like it could be anyone's game. There's just a few things we all have to worry about.
1. How much top brand appeal has Wii lost?
2. How big will the likes of NSMB Wii, Tales of Graces, FFCC: Crystal Bearers, SW3, Taiko 2 be towards creating a prominent lineup for a strong holiday season for Wii?
3. How big will FF13 be for PS3?
4. Is it possible that PS3 "peaked" before the holiday season like it did in 2007?
These are really the questions that matter in deciding this and if they even out in positive and negatives for both we might see a virtual tie. But if one dominates the others in these answers then we'll see some distance.