I ... I'm the only person who thinks that Gwen Stacy sleeping with Norman Osborn makes sense, aren't I? *hangs head*
Gwen/Norman is to pre-OMD continuity what "The Crossing" was to Tony Stark, and it really would take a Kurt Busiek-level talent to redeem that story.
Moreover, even if you think that the story itself is good (which you already know I don't), I really don't see how you can defend what it's led to, which is basically the full-on Villain Canon Sue-ification of Norman Osborn. Let's not forget Gwen/Norman was NOT JMS's choice, but was instead IMPOSED on him by Quesada, and when Quesada talks about it, he frequently mentions how "handsome" and "sexually charismatic" Norman is, which I believe has directly led to all of the equally OOC portrayals of Norman as The Villain Who Is Loved By The World And Is More Competent Than All The Heroes (not to mention that it was used as a justification for Norman impregnating Lily, and has been referenced in all sorts of creepy and trigger-inducing HE LOVES YOUNG BLONDES HAR HAR HAR jokes made ON-PANEL BY THE CHARACTERS THEMSELVES in all of Marvel's titles).
Sleeping with Gwen was the second step in turning Norman into the worst character this side of Superboy Prime (the first step, of course, was in bringing him back at all, because while it provided an effective conclusion for the "Clone Saga," it also set the precedent for every story that followed, in which every bad thing that happened to Peter and his loved ones was masterminded by Norman).