I was referring only to the first party issue. How many of your beaten games were first party? I'd say that the hardcore gamers (hate this name, but I hope you understand what I'm saying) tend to own more than one platform, so I don't think anyone who wants to buy 20 games per year is going to own only one platform. Everyone knows that Nintendo consoles are not the best candidates to get most of the third party titles available, but they'll get Mario, Zelda and the others. And it's here where I don't see any problem with the pacing of the releases for now.
Regarding the third party issue Nintendo did a good job getting third-party support for launch (they got the 3 biggest third party titles of the year if I'm not mistaken (blops 2, FIFA 2013 and assassin's creed 3)) but they didn't seem to plan anything besides the launch so we're looking now at a barren scenario. The big games (gta, bioshock, dead space...) have no Wii U version announced (and probably will never have) but now it's the time to talk again with activision, ea, ubisoft... And make sure that their big fall hits (call of duty, battlefield/Fifa and next assassin's creed) get a Wii U version. We'll see if Nintendo is doing its homework.
The bolded is the core of Nintendo's issue though, right?
If core gamers are only really buying a Nintendo system to play Nintendo games, and treat other devices as their primary gaming machines, then why would they pick up the Wii U versions of third party core games?
They're already heavily invested in another platform. If multiplayer is of interest to them, then presumably all their friends are on that platform as well.
Then, if the core audience for these third party ports isn't buying them in significant number, there's no point in third parties making them, and thus they don't go out of their way to develop them, which further reinforces the notion that Nintendo consoles are only for Nintendo games.
Either Nintendo needs to make and release games that keep the core audience constantly using the Wii U, or they need every third party game available (presumably through notable monetary incentives since many publishers are assuming it's not worth their while otherwise) so at least a core consumer has the option of making it their primary game machine.
As soon a drought sets it, it just sends people right back to their other machines instead of getting more invested in the Wii U. That's the biggest problem with having them in general.
To tie this more to Japan, if I was thinking about buying a Wii U, looked at upcoming console games, and decided what I really wanted to play was One Piece Musou 2, Dynasty Warriors 7, Lightning Returns, Dark Souls 2, and Metal Gear Solid V, my only option would be to just keep using my PS3, since as it stands none of those are actually on the platform I was thinking about getting. If that was the case, it's very plausible that I would just decide to stick with my PS3 and not bother picking up a Wii U until it had what I really wanted. If the Wii U had all of those games on the other hand, it would probably seem a lot more attractive than it does right now.
So I ultimately feel that they either need to A.) greatly increase first party output both in volume and variety to substitute third party support or B.) nail down across the board third party support to achieve what they seem to want to achieve (a system for Nintendo, "casual", and "core" audiences).