Usually when I propose things like this, they're shot down
pretty fast, but here goes anyway.
It took me a while to mentally connect the names of the
vertical spacing variables with their specific domains. For
example, I think it's counterintuitive that
'after-title-spacing does *not* affect the spacing after a
title when it's followed by another title or markup. The
appropriate one for that is 'between-title-spacing. Also,
some confusion arises before getting used to the fact that
markups are also referred to as "title".