Just finished watching it again. Started at 12 but had multiple interruptions.
A lot of the film makes sense and works well as a story that concludes the adventures of Peter, MJ, and Harry. The Venom bit of it didn't feel as badly tacked on either nor did Gwen Stacy.
What I don't get is why the hell did Sandman have to be in it?
The character only complicates/short changes all the other important elements while really contributing nothing to the plot.
Sandman being retconned as Ben Parker's killer has virtually no real bearing on why Parker turns evil. It pisses him off for a bit but then after his talk with Aunt May is pretty much fine again. The real catalyst for him turning evil in the end is Harry coming out of Pineapple Express state to mind f*ck both him and MJ. This of course sparks up the rivalry between him and Harry which completely defeats the purpose of his encounter with Sandman in the beginning. The Roxbury montage worked as did Eddie Brock's humiliation/firing and would have been plot enough before the final showdown.
I think Spiderman 3 would have survived just fine without Sandman and more exploration on the Eddie Brock Venom/Stacy Gwen character. I think aside from being humiliated and fired because of Parker, there should have been a bit more focus on the Brock/Stacy relationship. The subplot is properly introduced during the saving Stacy Gwen scene but left hanging and doesn't come up again until he's like "BTW, GF dumped me, sob so I going to kill you for that too"
I can kind of except the Harry Osborne redemption story but having Sandman just up and quit when Venom gets killed is just painful. The redemption leading from already idiotic retcon is nothing really more than a big f*ck off Sandman your not needed anymore for the story. Which is funny because he wasn't at all necessary for any of it IMO.
Spiderman, Mary Jane, Harry, and Eddie Brock/Gwen Stacy would have been more than enough plot/subplot the third time around and as such would have made a much better movie.
Ho hum.