[jcromartie]

I think the difference is that "flat design" is not added to a good information architecture. It's just what you get when you resist trends to add textures and widgets that don't belong.

I think your own example illustrates it: a film without special effects is just a film.

[mikecuesta]

Well... you still kind of need to add colors, fonts, and even pixel perfection of elements, so in essence you are still doing that extra step after the initial IA, just with a certain restriction.