Steven Johnson has an excellent essay in Time about the iPad, its shortcomings, and what we might (or might not) see in future updates. As he says:
The iPad interface — like the iPhone’s — tries to do everything in its power to do away with documents and files. There is no Finder or root-level file navigation. It’s apps, apps, apps, as far as the eye can see.
Read more: Apple iPad Shortcomings Spark Questions about Updates.