You can't make a billion dollar box office movie that only costs $60,000 using Carnage. The only Marvel villain that could cross that threshold is Dr. Doom but you can't make a decent Dr.Doom movie for 60 grand. Not that Diet Doc Doom Robert Downey Jr. El ctric bugaloo count as everyone knows that character won't remotely resemble comic Doom.

When you throw something you use more parts of your body than just your arm. Having a metallic arm with super strength is mostly meaningless if other parts of the body is not enhanced. His grip strength would be super. That's it. He lifts and throws her he is using his back. This is common sense.