The best example of Japan's taste in games would be Zelda : TP, it was designed to have a western appeal, and it's sales in japan have been in line with that, soon to be tripled in total sales by Wii Sports. The same can be said of most Wii games in Japan at this point, there simply aren't that many that appeal to that audience. Dragon Quest Swords is Square-Enix, therefore 3rd party. Expecting DBZ to do good in japan is silly, it's a 20 year old series there, it took over a decade for it to catch on in North America. One Piece, I think, will be a much better scale of how well a licensed title can do, if it turns out to be a decently good game (I look forward to it myself).
Nobody is crazy enough to accuse me of being sane.