>I quite understand this. Natural container with collections was the main feature that attracted me to use formsets. Gradually, I got understanding that I could and should enforce application objects hierarchy (through coded collections) myself and formset became redundant.

Yes, I do this too, but instead of the traditional oApp object, use the top-level formset in almost exactly the same way, so that the application object became redundant for me...I think they're functionally quite similar, so long as all apps will use top-level structure...