To provide a basis for what I want to say:
As can be seen from charts of all kinds, Wii was a great commercial success for Nintendo. It has sold the most out of the Big Three worldwide, and it's games have sold most also. (According to Wikipedia atleast.) However, I think the true success of this generation will be tested with the next. We know many casual gamers bought Wii but didn't get that many different games for it. You can see the casual effect from the Top Ten of best selling Wii games. Will Nintendo be able to excite these customers to upgrade to Wii U and can Nintendo get the hardcore audience back on board?

Nintendo markets the Wii U as a continuation of Wii, as is evident from the name and support of past games and peripherals. Wii U is a new platform with new features, but it retains everything good Wii had.
But what about after a few years? It has already been practically confirmed that Wii U's graphical capabilities are only a little better than current gen competitors. How will Nintendo ''keep up'' with the competition?

What has Nintendo planned for the future? Will they continue the Wii brand with a simple hardware upgrade with full support of everything related to Wii, or will the next Nintendo platform be something different altogether?

I think after this coming generation we will see something completely different.

3DS and Wii U are continuations of the DS and Wii.
I think after that Nintendo will drop the brands of those two, which were established quite a while ago.

They have to move on sometime.

I'll tell you in 5 to 8 years tops

Nintendo will give up with the Wii and DS consoles and create something new eventually. When though? We have no idea.

The DS and Wii however have been commercial giants for years but it has been alienating the "hardcore" gamers. I think the 3DS and Wii U were developed to regain their trust, after which they'll probably release a new line of consoles.

What I want know is, will Nintendo keep 3D for their handhelds? Or is the 3DS a one time project never to be repeated?

Something new.

Wii P

superWiiEntertament64cubeU
And HDSi SuperLLAdvanceBoy&Watch

Wii P and HDSi, LOL.

I was just wondering... They know that Wii U won't be sustainable any longer than Wii was, that is max 5 years. But I can't see them giving up the Wii U Gamepad if it proves a commercial hit. The same goes for the brand. I have this feeling that Wii U is an affordable way for Nintendo to launch the Wii U Gamepad and their improved network so they can be utilised in a future system, which won't be in such a distant future.

It is possible they'll explore things like cloud gaming, where you wouldn't need fancy hardware, but I think Nintendo wants to keep traditions alive as long as possible. It's very hard to see in the future. Wii's motion control remotes as well as Wii U's second screen thingamajig gamepad took us all by surprise, so it could be possible that some unexpected technological miracle could be that will wow us with Nintendo's next magical box.

Also, the two screen mentality will probably see continuation. But maybe the HDS (thanks LordOtakWiiU) will finally embrace capasitive techmology. About 3D I don't know... I've got the impression that the 3D isn't the point why people like the 3DS. I like it, but I don't always use it. It's somewhat cumbersome. It would really help a lot if the sweet spot was wider.

I think it is too early to say...we don't know what the Wii U will bring to us later in life....

I always thought after the wii u the next big system would be a HDS ( a Hd ds) but I agree after this generation I would like to see something new and not continuations of the same systems but with more power

It will probably be in 5 to 6 years that we'll see the next Nintendo console. That is the average life cycle of each Nintendo console so far.

I imagine the next Nintendo console after Wii U will no longer sport the "Wii" branding. Nintendo has a cycle to their consoles. The NES was something new, the SNES was an upgraded NES. N64 was something new, GCN was an upgraded N64. Wii was something new, Wii U is an upgraded Wii. Then the next system will be something new.

As far as the DS systems go, I doubt they're going to do away with the dual screens, so I'm not sure if they'll leave the "DS" name behind yet. It's entirely possible, though. We will see the new iteration of their next handheld within 2 to 3 years, as the handhelds come out in the middle of console life cycles. I think it will have all the same functionality as the Wii U GamePad. Two circle pads that are clickable, four shoulder buttons, etc.

After the Wii U? A controller peripheral for Apple after Apple acquires Nintendo.

Hah, I was actually thinking about how this should happen the other day

I think they'd both benefit a great deal.

Uh oh. Here comes the flames

Who knows. I gave up predicting Nintendo a long time ago. I never know what they'll come up with. I just hope it's something interesting and new.

I just embrace them at this point. I figure it's good practice for when I go to hell.

I've been wondering this too, hmm..

Not gonna happen as long as Nintendo does as well as they do. They have a very profitable business, even though they are not perceived as the leading company.

A very interesting point of view. It's very likely that there will be some interesting new technologies that Nintendo will feel is going to benefit the gamer. Personally I'm hoping for even more advanced motion sensing and voice recognition that will support or aid traditional gamepad controls rather that steal the main show. (Writing this I realize Kinect tries to achieve these but don't deliver in the way I envision, also the Wii U is very interesting with it's multiple control options.)

What? That has nothing to do with anything.

Profitable companies are purchased all the time. That's usually why they are purchased, because they are successful and larger companies can make them more successful.

Failing companies are the ones that don't get purchased often, unless to be broken down. Your logic is completely backwards.