I mentioned yesterday that I'm not clear on what the in-story reasoning is behind the death of Gwen Stacy. This stems from me being unclear on Norman's knowledge of Peter's identity, with regards to nobody remembering now. Does that mean Norman never knew? Does it mean he knew, but no longer remembers (a more long term version of those bouts of amnesia he had back in the day)? Is that's the case, does Norman realize he used to know who Spider-Man was, but doesn't anymore? I don't think the last one is likely simply because I figure if Norman realized he knew who Spider-Man was once, but can't recall that information now, he would do everything possible to extract that information from his head.
I imagine Norman doesn't even remember that he knew who was under the mask once upon a time. Which raises the question of what he recalls as the reasoning behind flying into Peter's apartment, finding Gwen, and carrying her off to a bridge to await Spider-Man's arrival. Thanks to the Fortress Keeper, I know that Osborn currently (as of New Ways to Die) believes Spider-Man takes photos of himself, and has Peter to sell them, so does Norman wonder why he would abduct Parker's girlfriend to strike at Spider-Man, or why Spider-Man would be so enraged at her death that he would have nearly killed Osborn?
Of course, none of that hampers Sins Past, which argues that while the Goblin might have been eager to hurt Spider-Man, he was equally as eager to get Gwen to cough up where she hid "his" children, and she died, as was thus unable to interfere with his search, so much the better. But, as I've mentioned, I'm not a big fan of Sins Past*.
Then I had an idea. It came to me when I considered that Angel/Angelus as Gwen/Norman thing. There have been some stories that delved into Norman's past, in the time before Peter Parker became the Amazing Spider-Man. They generally suggest that Norman's wife died when Harry was very young (a baby or not much older), and that it had a damaging effect on Norman. He probably threw himself into his work even more, neglected Harry (perhaps because he didn't know what to do), shut himself off. Early on, Norman might regard her death as a great loss in his life, but what if, later on, he sees it as the moment he was freed to become something greater, the Green Goblin? The Goblin can do whatever he pleases (except when that accursed Spider-Man interferes). No one can push the Green Goblin around, or take anything from him.
Is it possible that Norman could look at Harry, see him as too weak, and decide a little tragedy might toughen him up? While Norman wasn't heavily involved in Harry's life, he might be perceptive enough to realize Gwen is the girl Harry's really sweet over (or maybe Harry had told him that, again, I'm not really that familiar with the stories from that time period). I'm not sure about the idea myself. It seems like Norman has been most concerned with an heir since his return from death. he had stayed hidden to give Harry a chance at becoming a man (Peter Parker: Spider-Man #75), for awhile there he tried to make Peter into his heir (during the Mackie/Jenkins era), and when that didn't pan out, suggested he might try with Normie, sicne a young boy is probably easier to mold. Back in the day, Norman was probably more concerned with soldifying his power, his wealth, but if the Clone Saga retroactively made him a mastermind, capable of manipulating people all over the world, from thousands of miles away, I think we can retroactively make him concerned enough about his son's progress to take a drastic step.
For what it's worth, I think the original reasoning is the best one, but I figured I could throw this one out here, for you to mull over.
* Not so much because of the idea of Gwen and Norman breaking out the freak nasty sauce, though I would generally have figured there'd be mind-controlling drugs involved. But Gwen's a caring soul, and Norman was torn up over Harry's problems, and well, people make bad decisions all the time, so I can roll with that. it's more because I didn't appreciate yet another story where Peter gets all torn up over Gwen, and we're reminded of how much he loved her, and blah, blah, fucking blah. Sorry, gwen was dead for 15 years by the time I started reading Spider-books, and she was not getting brought up at every drop of a hat back then, and I was quite fine with that.