Super Mario 3DS will not feature stereoscopic 3D. Nintendo Life reports the news after seeing the North American box art which clearly states "Plays Only In 2D" on the cover...
I don't want to say this wasn't expected, because the original doesn't utilize 3D in any way, but it is a bit disappointing. So basically SMM3DS is the Wii-U version minus online uploading of levels, mystery mushrooms or amiibo functionality. I'm a little disappointed. Usually, Nintendo isn't so sloppy with their ports and they could've done much better with this one.