I find that I would like to expose different levels of detail in my org mode buffers; especially while reviewing possbile next steps across many projects.
org-shifttab
comes close. It will cycle from fully folded to expanding all of the headlines.
I would like to add the ability to cycle through the visibility of headlines at level 1, then at 1 and 2, then at 1, 2 and 3... you get the idea.