1. Semantic and document centric desktops. One of the things that makes apps like iPhoto so successful is that they focus on content as opposed to simply treating content as a set of uninteresting files. I'd like to look at ways to extend this and integrate into directly file managers.
2. New ways of organizing and grouping files. (This is an extension of 1.) Files are currently only grouped by location. They can also be grouped by people, type, date, and so on and so forth.
3. Zooming user interfaces and new-style folder icons. Instead of displaying folders as interesting objects in and of themselves, I'd like to experiment with treating folders simply as a collection of files. (Perhaps show the contents on the icon?) In particular, I think that file managers with zooming user interfaces could handle this quite nicely.
I know that some of the above ideas are a bit radical, but I think that even moderate versions of them could help users. Even if I can't attend UDS, I'd like to examine different aspects of each of them and determine what in fact would help users and which ones are implementable without changing traditional designs and frustrating users.