And I just had a simple idea which could improve the bad formatting.

It would be reasonable to convert a double-linefeed combination into "<br /><br />". This would save me a lot of typing and make much of the unformatted text more readable. The only trouble would be that you might not want to do this if there is already a "<br>" or "<p>" between the paragraphs. If necessary you could add a checkbox to "Preserve blank lines", allowing people to turn this feature off if necessary.

Just a thought, but this would make it much more convenient for me when posting since typing all the format codes is cumbersome to say the least.