This is kind of a paradigmatic change. Right now, the default when dealing with files is to point to them. What I envisioned in the grandparent was to make search the default. Tags, descriptive names, and locations are all search criteria.

In a way, it is more complicated: instead of 0 or 1 file, you now get a whole list. On the other hand, everyone understands search. My hope is, the initial extra complexity would be dwarfed by the ease of sorting and finding your files. Because right now, one or the other is difficult: it's hard (or at least bothersome) to properly sort one's data in a directory tree, but it's even harder to find it if your disk is messy.

Now there are two snags we might hit: first, I'd like to do away with unique names, because they get us back to the old, difficult to manage, directory tree. Second, to have good tags, you have to internationalize them. For music stuff for instance, French speaking folks would like to use "musique", while English speaking ones will use "music". It has to work transparently when they exchange files, or else it would defeat the purpose of default tags. I can think of solutions such as aliases, normalization at download time, or standard tag names that can be translated by the system, but I'm not sure that's really feasible or usable.