I'm not sure it's the same scenario since the product is called the 3DS and it would be more expected to include 3D in all offerings considering the nature of it's name, similar to how all DS games utilize the DS=Dual Screens. The Wii is just a made up word. It has no tie to motion controls. Your argument seems to tie more into the touchscreen, gyroscope, accelerometer, camera and microphone functions of the DS as opposed to the 3D functions.

Also how many Wii games really don't use any motion controls whatsoever?

A good number don't, even some Nintendo games.

I think you're making assumptions that aren't grounded in facts, just because its called the 3DS doesn't mean games have to use 3D, it just means the system is capable of 3D, the name doesn't force games to use all the features of the system, developers will try to use 3D wherever possible, but if its just not doable, they will skip it.

I doubt we'll see games where we're forced to turn off 3D. The gameplay will occur on the top screen, not the bottom. We can still use the touch screen to control what happens on top. It's not that difficult.

For a game like Trauma Center, you can use the touch screen while a reticle (or a scapple for ex.) appears on the top screen.  And to perform an action (incision), use one of the shoulder buttons.

The days of gamaeplay occuring on both screens are over. Like I said earlier, don't expect action to hop onto the bottom.

The only way I can see 3D consistently work for games like Trauma Center and Contra games is that the 3D effect is able to come out of the top screen but towards your point of view at the bottom screen. This means the player is able to do the surgery in the bottom screen with the 3D effect covering the bottom screen as a layer. When the player looks back at the top screen, the 3DS camera will sense the player's shift of vision, and the 3D effect will now be at the top screen. Basically the 3D effect from the top screen can reach the player's vision of sight at the bottom screen and appear normally.

For games like Contra 4, this could be hectic since players find it easier to look at both screens at one time, so it might force the player to only look at one screen at a time but have the 3D effect carry over to the bottom screen. Think, for example, an enemy in the top screen shooting bullets and when you look back at the bottom screen, you now get the 3D effect of enemies shooting at the bottom screen, but the bullet from the top screen will be visibly ontop somewhere by depth of the 3D effect.

I'm not sure if that made sense, but I hope it helps brainstorms possible ideas of how 3D can work games like Trauma Center or Contra.

Its a possibility, but if it detracts from the gameplay, I think we will see that some games just avoid using the 3D

I would say that using 3D for the touch screen might be less practical than it seems, since we are just manipulating things on a 2D plane anyway.

Now we do not know everything bout the 3DS so I’ll be crazy now and say that they still have not revealed the pointer ;)

You will use it as a tennis racket and hit the balls coming out of the screen… they do have a camera that can track it so you never know lol

Crazy thought though maybe next gen