Mostly of interest to font geeks, but U&lc has some tips (and reasons) for adjusting punctuation typography.

Sometimes a subtle adjustment in a character’s position can make a big difference in the visual balance of your typesetting. Case in point: hyphens, en- and em-dashes, parentheses, braces and brackets will often look fine in lowercase settings, but can appear too low when set next to caps and lining figures. The larger the setting (in headlines, for example), the more noticeable this will be.