That's a key point. A lot of readers here don't like to be challenged. Porn is a form of comfort food. Finding unexpected differences in presentation or composition can really ruin people's day. But you know what? Screw 'em. If they can't accept being challenged, that's their problem. I have two stories that really pushed The Reader in uncomfortable directions ("Across The Way" and "90Days ch.13") and the low ratings are proof that I did my job right. (...Mostly. The conclusion to "Across The Way" wasn't set up right, proving your second point as well.)
Long story short, you know what you're talking about. =)
I am sympathetic to the "comfort food" thing, although I don't always feel like making it. Sometimes I want to write the equivalent of black pepper cheesecake.
BTW I just read "Across the Way." You've got a talent for dialogue I lack... workin' on that one. When I wrote "It is Love," I cried, masturbated, and cried some more. I was in a very strange mood.