You've obviously never written a script before.
Which is fine. It's not something everyone needs, or should do. But, that also means you don't understand why Spider-Man 3 was didn't work.
Pretend you wrote a script. 123 page script. Your script contains certain elements, scenes, characters. It all flows well, and makes sense.
Now, imagine you're say....5 months, or so before filming, and someone comes to you and FORCES you to make changes.
Add characters, replace scenes, ect. You're going to have to change the story around to make these changes work. But have little time, and the clock is ticking. You can't stop the train now, you have to stay on schedule. You movie comes out in 1 and a half years. AND you have to cast, and start pre-production, all while you're re-writing the script,.
It won't turn out well.
The script had Vulture and Sandman, right? Well, even if Sandman was Ben's killer, it would've worked better, because we would only have to deal with the redemption of Sandman...if that was the case, and it wouldn't have come off so cheesy, because we would've gone through a journey with this character, rather then have him pop up every once in a while to fight. And the Vulture would be the main, evil villain, if that was the case.
Point was, without Venom, without the suit, we could've had a possible proper end for Harry, a better MJ relationship, a shorter run time, and a more compact story line.
Instead, thanks to Venom, the movie was ruined.
awesome, can't 
