The designers of GNOME and Mac OS and until recently Windows seem to think that document-centricity is enough. That the "Open File Manager"->"Open File" semantics is much better than "Open Application->Open File" and we needn't go further.
Yet I find myself still using the application-centric semantics (which are still provided though the application menu) even when the document-centric semantics are available. In other words, I don't open files with the file manager.
This is because the big problem with the application-centric setup wasn't the file opening semantics, it was the act of opening itself. The problem is that we are forced to switch between modes, in one mode working with files and in another mode working with data. Whether the file mode is housed in an open dialog or in a file manager is not important.
In fact, on Windows, it may be in fact simpler to use the application-centric semantics. In Windows, many applications remember what folder you were last in, so instead of having to find the folder where you keep your Word documents in the file manager, you can just open Word, click open, and you will be there.
So the document-centric approach hasn't improved either situation--multiple file editing modes OR managable file opening semantics. But information-centric systems (a la The Humane Interface) solve at least the first one, by having one mode for managing and editing files. And the second may in fact be solved by THE's zooming interface, I'm not sure. That's a separate essay.