Sub Articulo 55.1
If I understand correctly, it's not so much that the margins are large as
that the width of a single line of text is small. The human eye/brain is
more comfortable with a line width which does not force the eye to move very
far as it tracks along the line from left to right. On the other hand, you
want a sensible amount of text, or the eye has to keep scanning back and
forward at the end of every short line instead!
Research has shown that a balance exists, usually described as something
like 10-12 words or about 60 characters per line, I believe. The default
margins in LaTeX standard classes will provide roughly this line length when
using the default fonts.
Personally, I agree the defaults are overly large - not enough white space
is bad, but too much is distracting. I usually change the margins to make
them smaller than the LaTeX default.
Hope that helps - if I'm completely off-track, would someone please correct
me before I'm laughed off the group? Thanks :-)