Title levels and collapsing/expanding are great for structuring a long knowledge doc.
But it would be really greater for legibility and clarity to allow for indentation :
- of nested titles (when collapsed)
- of nested sections (when expanded)
Actually, I intuitively first searched for the same tabulation/indentation that is already available when formating plain paragraphs or titles with collapsing disabled. So maybe, making this available for titles with collapsing enabled would make the job, or at least a part of it.
Or else, it could be a global setting on each page ?