Although the "line breaks" section in the SQL Formatter "advanced" tab has a section dedicated to CASE it does not have one for IF / THEN / ELSE and indeed it seems that the
setting for THEN in a CASE expression affects IF / THEN / ELSE as well.
Deciding whether THEN should appear on the same line as IF is, in my experience, perhaps the single most emotive topic in code formatting in all languages and I would suggest an easy way for people to choose.
--Tony