this should be pretty easy but useful.  under Tools-->Options-->Formatting-->Java-->Blank Lines, add the ability to
insert blank lines before javadoc comments.  many people don't want to skip lines between self-explanatory field names
as this wastes space, so the blank lines before and after fields is usually left to '0'.  however, on the fields that
one does provide a comment for, it is more readable and aesthetically pleasing to skip a line, so that there is space
between the comment and the preceding class member.

since there are other conceivable use cases, such as not wanting to skip lines between method signatures in interfaces
unless there's a javadoc comment, it may be a good idea to make the option a bit more generic, such as 'Before/After
Members with Javadoc Comments'.  this would be the better option, but may be a bit trickier to implement.