Why do you think that PS4's launch in Japan will be much better than Wii U's?
The Wii U launched at December 8th (holiday boost) and with the successor of New Super Mario Bros. Wii, the best-selling game on a home console in Japan since the original Super Mario Bros. (NES). NSMBWii sold almost as many units in Japan as the four best-selling PS3 games combined. NSMBU had a attach rate of around 50% before the new bundles were launched, now it's close to 80%. It already sold more units than the third best-selling PS3 game.
The PS4 launches on February 22nd with no holiday boost. The highest sales will probably have Yakuza Ishin, the sucessor of a game that sold 0,59M units. It will probably sell more units on PS3.
The Japanese won't care much about Killzone, Knack, DriveClub or InFAMOUS a month later.
The fanfases of Call of Duty or Battlefied (the ones who highly influenced the western PS4 sales) aren't that big in Japan and the potential buyers probably won't wait until February.
The Japanese won't buy the console without interesting games and wait until 2015 to play on it.
Most PS4's that are sold today were ordered before launch and were influenced by the E3 hype. I doubt that a crazy amount of PS4's is still ordered today after all the game reviews are out.
I think the PS4 will have higher YTD numbers than the Wii U in Japan at the end of 2014, but it won't beat it's LTD numbers (maybe in 2015). It will almost certainly beat it's LTD numbers everywhere outside Japan, it already happened in several countries.
(Sorry, my English isn't the very best...)
