A few weeks ago John Siracusa wrote a great summary of the Finder, with specifics on why the OS X Finder is a step back from the OS 9 Finder. In the second half he provides suggestions for improvement that return what was good about the old Finder, plus a general architecture and guidelines for adding features.
And Tog writes that Apple has been squandering the advantage it used to have. Some of the interface innovations he wants include piles, file cabinets, and scrapbooks, all to help better organize documents. Just the names alone carry a lot of meaning.
eWeek hints at possible Jaguar “user at the center” features, including piles that Tog mentions in the link above:
"According to the patent, piles comprise collections of documents represented graphically in stacks. Users can browse the "piled" documents dynamically by pointing at them with the cursor; the filing system can then divide a pile into subpiles based on each document's content. At the user's request, the filing system can automatically file away documents into existing piles with similar content."