Unfortunately, the most common setting (and the very worst) seems to be to
have no space before or after and use the enter key to insert an empty
paragraph to get spacing between paragraphs. *

Well, as I mentioned in another post, that it exactly how it was done
by the MS people who wrote the Word manual (back in the days when
there was a manual).

They weren't entirely brain-dead. They defined a style called
"ParagraphSpace", or something like that, and then you can make global
chnages by changing this style.