Sticky:
Read this before Posting PDF Questions
The problem is not that the recommendations didn't work.
The problem is that not even the recommendations are capable of fixing the catastrophic damage that was done to your book by turning it into a PDF.
(At least, I assume you tried various line unwrapping factors and failed to hit on one that satisfactorily merged together the majority of badly-split paragraphs.)
You may be able to get better results by using professional (and
expensive) OCR software like ABBYY Finereader.
However, either way you will rarely be
lucky enough to get a "perfect" conversion. As dwig said, you will usually have to edit the EPUB manually in order to clean up the various errors that are inevitably left behind by a PDF-to-EPUB conversion.