One continual source of frustration with OF is that it often does not show the context I need for each item. For example, in the Flagged and Tags perspective, I would like to see the parent item of children. As it is, children are essentially disembodied. You can see the top level and the tags, but not the parents. Thus, for a project like this:
Book air travel
Arrange for pet sitter
call to confirm
You end up with things like:
Luxembourg (Plan Vacation)
Home (Plan Vacation)
call to confirm (Plan Vacation)
Where’s the context? Why are parents treated like second-class citizens, with only children shown? I understand the GTD emphasis on Next Available Actions, but it’s the parents (and parents of parents) that are the goals of the children (tasks).
Compare this to Things, which goes the opposite direction, showing the parents (goals) and only when you drill into it do you see the children (tasks). This also has some limitations, at least in their implementation, where you can’t have deeply nested projects, but honestly, I’ve been contemplating switching based on this difference alone, as OF’s parent-hiding is just not compatible with how I think of my projects.