I'd agree that the current glasses-free 3D displays are gimmicky, and the Nintendo 3DS will likely be underwhelming. Somewhere down the line when 3D displays improve, 3D plus a Retina Display resolution could combine to be stunning. Apple could make it work, and I'm sure not everything will be 3D (though even the UI elements in Safari may have some depth if it's worthwhile).
3D may still be fairly gimmicky now, but it's not going anywhere, and it'll only get better. Glasses-free 3D is definitely the future of that, and it shouldn't be long until 3D content will look as realistic depth-wise, but will be more stunning than the real word. With the right UI, an iPhone with a 3D display could even have interface elements seem more natural, since we are used to a 3D world after all.
3D may still be fairly gimmicky now, but it's not going anywhere, and it'll only get better. Glasses-free 3D is definitely the future of that, and it shouldn't be long until 3D content will look as realistic depth-wise, but will be more stunning than the real word. With the right UI, an iPhone with a 3D display could even have interface elements seem more natural, since we are used to a 3D world after all.