Sentence Length and Readability

I have done a lot of research regarding sentence length and readability. In my view it is a fallacy to say that long sentences make an essay harder to read. Indeed professor Brooks Landon of the University of Iowa has explored the are of creating great sentences and is of the opinion that long sentences can be used to aid readability, provided of course that are well constructed sentences, indeed it is construction that matters most when crafting good sentences. I understand the Flesch-Kincaid or Gunning-Fog indices should only be used as a guide, too many seem to think them to be hard and fast rules.

Even long sentences can be imminently readable, provided the propositions flow from each other and build to a climax.

My point is that I disagree that sentence length should be used as a primary method of defining readability. I would like to see the percentage of long sentences increased.