Right now we have expand/collapse (top level) and expand/collapse recursively (every level, which gets messy), it would be great if we can expand everything at say, 2 levels down, or 3, by a shortcut like maybe shift+control+2, shift+control+3.

Use case:
I keep a project named "books", under that is different categories of books, "self help", "entertainment", etc. Under that is actual names of the books. Under the names is notes for the specific books. It will be great if I can expand everything up to level 3, where I just get a list of book names I'm reading, or level 2, where i can see just all my categories.