A few things should be mentioned right here right now: I do not own a Wii U and I love Nintendo - this won't be a critique of the company or fanbase.
I was an early adopter of the 3DS (I know, f*** me right). Amongst the speculation, I genuinely believed the 3DS would pull through - I remember the first DS launch, of which my 10 year old mind decided the best game was the remake of Super Mario 64. This in itself wasn't a good sign, remakes should not be the best game on a system (Persona 4 on Vita anyone?), but my little brain never worried for I didn't know the concept of a games console failing. Therefore, with a few Mario games on the horizon I believed and prayed that the 3DS would make the doubters feel like the cynical idiots they were. The 3DS prevailed.
The question now is, will the Wii U pull through the slump that the 3DS did? I think probably not, they'll have a snug 3rd place in the runnings of the next generation.
The issue with the Wii U is that it doesn't have a great deal going for it. 3rd party support is lacking. 1st party development has one truly good game on the horizon: Pikmin 3, a game that will only satisfy the core gamers and Nintendo fans. Remember a time when Nintendo's home console was being pulled along only by 1st party support to the dedicated fans? Oh right, yeah, the Gamecube.
I don't think this is a bad thing, but atleast the Gamecube had a few things going for it. The graphics power was ahead of it's main rival, the PS2 and the first party support was truly great. The sales were bad, but this was thanks to more the brand of Nintendo as a kiddy system. As much as they pulled away from this ideology in the era with games like Metroid Prime, the Wii has truly revoked this image with child friendly advertising and games (and keeping the name won't have done them many favours in trying to shake the image).
Power isn't this consoles strong point. Let's hope Nintendo pull out some good games and they will hopefully get enough sales to survive this generation. If not, who knows what may happen to the Japanese giant - no company deserves the fate of Sega.