Most of Nintendo's titles are sadly bombing/underperforming in Japan on Wii u.

What the hell are these wii u owners playing then?

For Example:

The only titles over 25% in attach rate in Japan are as follows

MK8

SSB

WPU: got lucky due to a great bundle

SM3DW

NSBU

Now Lets look at the titles that you could consider bombs by going by media create/famitusu

DK Tropical Freeze: 35k(lowest in series debut)

Dragon Quest 10: 44k(wins lowest in series debut by a lot)

Kirby and the RC: 32k(2nd lowest in series debut)

Mario Party 10: 50k(lowest in series debut)

Bayonetta 2: 38k Debuted higher on the 360(a dead console in JP) with less than 1 million install base vs a 1.7 million install base

Fatal Frame 5: 38k Luckily for this most of its games debut around its number

Captain Toad: 28k(got lucky due to holidays for its legs)

These are few of the many examples of games that have underperformed in Japan.

So I ask you this 

do they need more variety and what do you think they use there wii us for if they oly buy(most of them) 3 games on it?

Yeah Japan needs to get their shit together. What are they even buying?

Japan doesn't need to do anything. It's not their job to buy Wii U games. It's Nintendo's job to entice them to buy Wii U games.

Nintendos Wii-U strategy failed not only in Japan. Instead of focusing on games for small children, Nintendo needs to create more games suitable for adult gamers (and former NES, SNES, N64, GCN or Wii owners) and actively market the system towards them.

They also need to actively seek 3rd party support and cooperation and the tablet and price must both be dropped.

It's really amazing because it seems like Nintendo basically made the Wii U for Japan's tastes first (semi-portable console). It's been such a flop there.

...

Best... Answer... Ever!!! Nintendo's predicament seems to be everyone else's fault. 

Seems they prefer mobile systems. At least the Wii got some of them in from the outside but now they're back to being outdoors-dwellers. For the home they seem to prefer games which can be played with many people, so people who like getting some of that window-filtered sunshine are still extroverted and thus likely to still spend a lot of time in the dreary outside world. Oh well, even great civilizations have to fall some day.

I think this is going to be the challenge for Nintendo with NX ... not so much about getting the highest user base number.

Now that they have iOS/Android to work with they can appeal to the largest broad market.

With NX I think the question is going to be can they get back a userbase that buys more diversity of software on their dedicated platforms.

The N64 only sold 33 million consoles, but a sh*t ton of different styles of games sold great on it ... Mario, Mario Kart, Smash Bros., Zelda, yes, but GoldenEye, Turok, NBA Courtside, 1080 Snowboarding, Star Wars, Wave Race, San Fransico Rush too.

The 3DS has some OK diversity with things like Monster Hunter (even in the West), Fire Emblem, etc. selling higher than expected but they need to push it further.

Wii U is not an attractive console because Nintendo didn't bring the games the market wanted in a home console.
Also, it's a result of Nintendo home consoles not doing that since, basically, the N64. And because of that, they can't make good deals with 3rd parties unless it's a partnership.

Dragon Quest 10 already had made it's userbase on Wii; Kirby RC also looks out of place on Wii U.
DK and MP 10 are unexpected failures but the other are pretty much expected.