3d is nothing more than the hardware makers desperately trying to find a new reason to get consumers to buy new hardware. They know the HDTV market is pretty well saturated, however if they really think 3d is gonna be the 'next big thing' like HDTV is, they're sorely mistaken. Anybody can sit down in front of a HDTV after looking at an older regular TV and go "Oh, well holy shit." However convincing them that they'll have to wear those glasses the whole time while watching tv for what is essentially a gimmick that a lot of people don't even care is going to be a VERY hard sell. 3d is fun for movies you go and see in the theater. You sit down, put on the stupid glasses, watch your movie on a bigass screen and go home. On the small screen though, well, I remember going to Nvidia's 3d booth at PAX last year and I saw a lot of gamers try the system out (same style of shutter glasses that the tv 3d would use) and walk away kinda unimpressed. I tried it out and walked away with roughly the same reaction "looks neat, but not worth it (and fuck those glasses)."
And since the OP mentioned them in the title:
Motion controls are a good idea implemented VERY badly. If you want an example of motion controls done right, then go check out the TrackIR. It's kind of a niche product geared towards the sim crowd, but I have one and it's fucking awesome. It also has the massive advantage of being a niche product meant for the sim crowd with a very specific use. It makes it easy for developers to code it right in (since all it does is allow you to look around in game just by moving your head around. This is horribly vital in a lot of these games) and thusly the product does very well since the market exists and the developers are willing to support it. After all, all of these games are playable WITHOUT the TrackIR system. You'll just be using a hatswitch or numpad or whatever to look around instead. This also helps to drive TrackIR sales since gamers can still play their games, save up their pennies and eventually get the TrackIR so that they can be even more competitive in multiplayer.
However on the flip side, he Wii's controls are just a dumb gimmick that went nowhere, and Sony's bullshit won't be any better. The Natal has potential to act like kind of like the TrackIR, but that would involve the game developers to intentionally take advantage of it and I highly doubt console games, which are meant to be a mass market, wide audience sort of affair, will ever treat it as anything other than as a stupid toy.
There is a lot of potential for fantastic uses of motion controls, but it sure as hell isn't going to happen with the current mentality that most game developers have.
