Ok, I just saw Avatar today (3D version, and loved it completely). After thinking about it later, it finally hit me - and it was so obvious... its obvious.

The common conception was that the "Wii" would be followed by the "Wii HD". Nintendo stated it wouldn't happen - there is no obvious gameplay benefit to have HD over non-HD after all.

But at the same time - Nintendo would love an 'excuse' to put out an updated Wii sometime in the next year or two (think DS --> DSi). Any upgrade from here onwards, would be a soft upgrade - the Wii has been successful enough for them to keep riding on.

Yet at the same time - the Wii 'tech' is starting to look dated. Big games are now skipping the Wii - most of the obvious Wii ideas have been done. Nintendo will need something new soon, to refresh things...

...

Enter "3D".

A "Wii 3D" would be the perfect tonic - maybe for a Xmas '2011-12 release. And here is why:

 - the same way that motion controls defined gameplay changes for this generation, 3D would define the next set of gameplay changes. I can immediately think of ways to incorporate 3D into different gameplay models (think of a Super Paper Mario game).

 - 3D is coming anyway - and Nintendo would not want to miss out. Of all the consoles, the Wii is the only one that may really struggle with it technically

 - a Wii 3D would be completely backwards compatible (drop GC support though), but add support for enhanced 3D games. Like the DSi, it would be faster, have more RAM, more memory, etc.

 - "Wii 3D" launch titles: Nintendo could easily be working on a host of 3D launch titles for the system (Retro?). This is the biggest barrier to any new release from Nintendo these days. The new Zelda could easily be a launch title (while also working for the current Wii). And may be why we haven't seen a lot of new 'future' stuff from them.

 - easy marketing campaign, and selling point. It also means they don't look like jerks for not including HD with the Wii initially.

 - consoles can make 3D run on existing TVs (do not need a new TV AFAIK... ) - as long as people have the glasses.

 - its an easy excuse to refresh a lot of their IPs already out. Imagine a Vision Training game on the Wii for 3D, or an updated Mario Kart 3D.

...

Anyway, just some thoughts. I could be completely off the mark - but I do think a "Wii 3D" makes a lot more sense than a "Wii HD" refresh...

Virtual Boy.

Edit: A topic that probably took a bit of time to type up deserves a bit more than that. Originally I thought you were talking about the 3D TVs that are brand spanking new and had a reply based around that. Let me change gears for a moment.

The existing 3D technology just isn't that good. The illusion isn't that great, and it gives most people a headache after a little while. There are a lot of interesting new developments that could be cool once games actually start taking advantage of them, but that is not a step for next gen. Certainly not for Nintendo at the current moment. Without using the latest iterations you will get a cheap, and mostly useless effect that won't help win over anybody, and likely won't lead to anything new.

I also completely disagree with the premise that the Wii is dated. All the obvious ideas might be up, but what does that mean? Big games are not suddenly skipping the system either. Games have not found a home on the Wii sine the begining of the generation, and I have seen no real change one way or the other in that regard. There are more Wii exclusives coming out that are worth something though.

Would 3D attract customers who don't currently buy games? I don't think so.

That's why motion control was successful but HD wasn't, the latter only attracted people that already bought consoles.

@Soriku: The quality of online, or HD, is not stopping non-customers from becoming customers. Something else is, and Nintendo needs to do that to make Wii+1 a success.

maybe you're right, it would be cool..... but it won't happen

3D halves the resolution, so you would need HD capability but would only get SD like results.

Would 3D require people to wear special glasses to play the game?

I've watched some Channel 4 "3D" programs and they ask you to put on the glasses at certain points.

Then they should just call it the WiiD.
Or the tWiiD.
Or the Tweedy.
Or just the Tiihii.

When I saw Avatar in 3D, I also thought that the same technology could be really immersive in video games. But I was thinking it would have to be way in the future, at least two console generations from now to be affordable. I think if the 3D quality was on par with Avatar it would be a huge advancement in video games, but I think if it comes out too quickly and all that be created is a cheap effect like when low budget tv shows try to do 3D it will be seen as too gimmicky (Virtual Boy) and not widely adapted.

"Big games are now skipping the Wii"

Big games are skipping the Wii because of lazy developers. Yes, I'm saying that sticking with throwing money at HD games is less effort (not in terms of time and money, but in terms of going outside comfort zones for developers, which can be a very trying thing for people) than making a game that works well on the Wii. It's safe and doesn't take as much imagination.

Back on topic, 3D done right would have the benefit of introducing depth perception in games. Too many times I've crashed a car, missed a jump, or missed a melee attack because I couldn't properly judge the distance. Sure the law of perspective gives one a general idea of distance in games, but it's the little things that make the lack of depth perception a problem.

3D doesn't halve the resolution, it doubles the refresh rate, so you need 120Mhz TV and game console.  In other words, most TVs being sold today can not handle it...

The next Wii capable of 120 FPS 1080p makes sense. That said, as long as Wii is selling more than 360 and PS3, it doesn't need to happen soon. Nintendo will milk the current customers as long as the wii is selling the best and no reason to release a new model unless the motion controls from Sony or Microsoft cause them to sell more than the Wii...