Points would be faster access, that it closes after choosing a file and last, but not least, that you _see_ what kinds of documents are in it, because you can see parts of their icons.
However, it would be enough for me if they brought back _full_ spring loaded folders (from OS 9). OS 9's Finder lets you 1.5-click a folder (holding down the mousebutton on second click, i mean), it opens and changes the mouse pointer into a looking glass. you can then go through the interiors of that folder and further down the hierarchy until you release the mouse button. then, all interim folders are closed and only the last window stays open. that's what i'm missing - and it's still missing in Panther.