My rating: 7.5-8.0
I saw it yesterday as well. I agree, the kid thing was unnecessarily put into the film. There were better ways to "re-introduce" Spiderman than that.
The Rhino thing didn't bug me. It was just their way of leading Spiderman 2 into Spiderman 3. The middle of the end credits scene had nothing to do with Spiderman 3 so they needed to segue into it somehow.
As to the climactic scene 10 minutes before the movie ended, even after I heard the slow motion snapping noise, I so did not think that it would end up the way it did. That little tidbit never happened in the golden age nor silver age reboot comic books. As to the current iteration/generation, I have no idea. I haven't read a new comic book in over 20 years.