Yep, Ari, I agree. A module's readability should be a high priority for the writers and developers.
Everyone would rather have a fun-to-read module than a boring-to-read one; the question is how much of the creators' energy should go into readability as opposed to other facets of the module. And I agree - it should be a lot of the energy. In my opinion, it should be the second priority behind playability, ahead of art, ahead of binding/paper quality, ahead of insane number-checking of the kind that would make John Cooper happy.
To this end, I think that Adventure Background sections should be eliminated from all modules. This would improve readability because the reader would feel suspense as he went through the module and the plot elements were gradually revealed. It's tangential to this discussion, but eliminating the Background Section would also improve playability, because the module would be forced to present the background information
in the module itself, to the PCs during gameplay, rather than leaving them in the dark and presenting the background info only to the DM in a separate, non-gameplay section.
I also think that too many game designers fail to pay attention to the rules of good fiction writing. Big shout out to Lance Hawvermale, though - he does. Good stuff from him.