I haven’t thoroughly read this thread so my apologies for any redundancy …
That was my a priori expectation (and hope), too, as I began testing EF today. Then I anticipated that selecting a folder containing subfolders and documents would display a list of the union of documents within each subfolder (like iPhoto/iTunes), basically creating a subset of the Library view without explicitly selecting (sub)folders. From there drilling down into the hierarchy would reduce the view to smaller subsets.
So far I’m left with the impression of EF having both a Finder-like and iPhoto/iTunes-like UI, which isn’t immediately intuitive or comfortable to me. I’d prefer it behaving closer to iPhoto than Finder (or even iTunes), with the Library being an unhierarchical view of every document and the ability to construct a variety of virtual hierarchies/views from it. Removing an EF “folder” (analogous to an iPhoto album) wouldn’t actually delete documents unless explicitly requested. And documents could easily appear in multiple “folders”. Sort of like tags, with the ability to be easily organized within different structural views (like TinyApps.Org’s “context”, as I understand it).
I think Yojimbo uses that kind of all-inclusive Library metaphor, but doesn’t support hierarchical views.
And at times I’ve been critical of DEVONthink for its dependency on rigid Finder-like hierarchy of groups, with the History window being the closest thing to a Library view. You can sort of simulate “the Library” by leaving every item in the top-level (root) group and cloning (aliasing) items into various group hierarchies, but it’s not designed to be used that way (I’ve tried; I’ll spare details of my failures).
Even if I were more familiar with other organizer/outliner apps this post is already too long to analyze them.
I’m no expert on the topic, but I’ve thought and written quite a bit about it over the past few years. The gist is how hierarchical filesystems and “desktop metaphor” have negatively influenced UI design. I see an increased urge (or necessity, for scalable usability’s sake ) to find and use design metaphors that can be more effective for organizing/managing ever-growing amounts of data when hierarchical boundaries are optional or dissolved. The relative proliferation of “o/o-style” apps on OS X, with similarly recognizable yet “slightly” different UIs with overlapping functionality, is one symptom of that effort.
I have great appreciation for what EagleFiler, DEVONthink, Yojimbo, OmniOutliner, KIT, et.al. developers are doing regardless of any personal preference for one of more apps in their category. And I’ve wondered if Apple’s lackadaisical Finder development is a mixed blessing in disguise as partial inspiration for some of them.