This is hardly a spoiler since most of it was in the announcement trailer, but you can imagine the 3D effects. They work quite well for this scene actually. And before you say ewwwww English dubs, I think the English voice actors sound better than the Japanese ones.
The 3DS actually adds depth to the screen and is hardly just a "pop-up book" effect.
Likewise for this cutscene, again mostly shown in a previous announcement trailer:
But that's 3D already. We're taking about 2D being 3D-fied. So what's already flat going 3D would best be like a popup
We're talking about 3D as in watching 3D monitor instead of CG 3D right?
Iono. I can definitely imagine any Gundam mecha series in 3D though can you not?