I think it would be nice to be able to background all operations, though I accept that this is quite a functionality change! I don't see any reason why this would create problems, although I suppose that you would need to deal with conflicting operations in the queue. Well actually, I suppose you don't need to do anything special here; for example, if you move a file and, while moving is taking place, you delete it, then the server will just complain when the instruction finally arrives to delete a file which is no longer there.