Using signpost paragraphs in an article
Scientific papers are generally read differently than literature.  Most people reading a scientific paper are not reading it for pleasure, but have some sort of agenda about what type of information they are attempting to extract from the paper.  It is only rarely that they will want to read the whole thing, but more often are attempting to extract particular types of information, which may or may not be included in particular sections of a paper.

As such, it is generally best to start each section (even of a non-review paper) with a terse summary of the contents of the section.  If you wait to put your summary further into the section, then it will simply annoy and frustrate many readers, since it will force them to read paragraphs they are not interested in before they get to the bit that tells them whether they want to read that section.  Worse, many will not get there at all!