Not supporting folders for apps seems reasonable. They probably want to simplify things and folders, while handy, aren't really necessary and can be confusing for the lowest-common-denominator. I'm surprised they haven't completely eliminated the desktop/drawer separation altogether like in iOS.

Presumably the final Facebook phone will have a very short list, so app sorting/scrolling features would be simplified for convenience and intuitiveness... I mean, what apps do hardcore Facebook fanboys need besides Facebook?