I really hope the WiiU has the chance to establish itself a tiny bit in Japan before the PS4 lands...

...I mean, the PS4 line up isn´t exactly great either.

Hang in there !

I was quite clear in my opening post that the question is about the Japanese console market in particular, since it´s the Japanese launch that was delayed and it´s in Japan where Sony systems are performing really bad this holiday season. In fact the holiday season surely was a big factor that helped in generating hype and sales and in regards to Japan would have helped PS4s launch-hype. Instead their decision actually helped their strongest competitor over there.

when sony launches and sells more than Nintebdo then youll have your answer

The WiiU was selling 3k per week when Sony made the decision to delay the PS4 launch in Japan. They didn't expect a big holiday boost for the WiiU in Japan. We still don't know how much WiiU will sell once the holidays are over. We also don't know how hyped Japan is for the PS4. If it's anything like Europe or NA, then they shouldn't have a problem. It doesn't matter anyways because the WiiU is going to miss out on a lot of massive Japanese games like FFXV, Kingdom Heart 3, Yakuza, MGSV, and so on. 

Dunno, i don't remenber a sucessfull launch of hardware in february(*stares at vita*)

You are not asking for what affect it will have to the Japanese market but whether or not it was the right move if we go by the title, and it was, despite the consequences.

Ignoring WiiU. It still is a stupid idea to miss the holiday season in Japan just to push PSV with PSTV (another big mistake similar to PSPgo) and to cash-in on Gran Torismo 6 and PS3 and missing out the holiday season (PS4). Now we have the data and know that it didn´t work out, especially Gran Tourismo 6 is a big disappointment beeing easily outsold by 3D World.

These are basically the reasons for the delay, because let´s be honest for a second, they could have as easily favoured Japan instead of East-Asia, Brazil and even Saudi-Arabia. They simply were to shortsighted if they really planned this according to post WiiU bundle announcement sales, when its sales had a noticeable decline due to this very announcement.

They simply believed that Gran Tourismo 6 would have been enough to have a decent holiday season in Japan.

Well, let's think about it. Sony has a finite amount of consoles which have to be spread around the world. They have zero worry about the Xbox One in Japan. I don't think they're very worried about the Wii U, either, to be honest. Really, so what if the Wii U is doing better than before? It's still not taking Japan by storm and they don't even share a lot of the same content.

People who want the games that the Wii U won't get will still want a PS4. I really don't think this is going to allow Nintendo to build some kind of critical mass for the rest of the generation. The Wii U probably would have sold nearly the same amount of units if the PS4 had released in Japan last month. The two consumer bases certainly do not overlap completely.

Does anyone really believe that this is going to change the fate of either console in Japan?

No they simply realised that they have no software for a japanese launch and thus made the smart decision to allocate their consoles to regions where people are buying the PS4 with the games it has. In Japan the console would've made no impact with the launch software it has. Japanese developers are still making alot of games for the PS4 that won't come to the Wii U, so missing out on this holiday season shouldn't matter.

Shortsighted? It would have been shortsighted of them to launch in Japan this year and not think about the rest of the world. They were thinking about longterm gain with the delay and I think they made the right call. They can win Japan, easily. And they will, just wait til February and you'll see. They'll have a launch of at least 500k units, followed by weeks of sellouts. Once the console stabilizes it will be outselling the WiiU 2:1 every week barring a major release.