I've always been a little puzzled by the C5 File Manager, a giant list of files that can be sorted by sets rather than presented as a tree with folders and the ability to put folders within folders and drag and drop files. I don't think I know another application that does not use the tree view to manage files.

Why aren't file sets folders within the file manager that can have additional file sets (folders) within them, looking more like the site map does than the current file manager?

It's how computer users are use to managing files, I think it would be a more intuitive interface.