Links should appear different, but not too different
Right now, simplebook removes the text-decoration and border-bottom from links so that default mediawiki pages don't show links in order to facilitate easy reading. However, that means there's no indication that something is a link. There should be a middle ground between aggressive text changing (needed for the web) and no text changing (needed for printout).
What that middle ground is is up to discussion, which would be the bulk of this issue. Once agreed upon, implementation should follow easily.