I loved the first Iron Man film. It’s really just a perfect comic book movie. Minus maybe the villain being a little tame at the end, the film as a whole is strong. Iron Man 2 went the other direction. Whiplash was a strong villain, with on the greatest scenes ever(Whiplash attacking Stark on the race track). The movie though was too cluttered and just all over the place. Now Jon Favreau is out and Shane Black is in.
To me the next and obvious villain for Iron Man would be Mandarin. The terrorist group from the first film was named “The Ten Rings”. Black though has come out stating Mandarin in the comics was pretty racist(it’s true), the character was just a walking Chinese stereotype. No one would want that. I would love to have the terrorist leader return, now having ten powerful rings and goes after Iron Man on a personal level.
Instead though it has been confirmed that Sir Ben Kingsley has landed the role as the main villain, and that he won’t be Mandarin. Now mind you that could not be true. Rumor is though that Kingsley’s character would be involved in the spread of a virus of nanobots. Sorry that is just not as cool as the Mandarin.