I'd say without Iron Man 3 it would have made 10% more. Bloody Iron Man.
With a good marketing compaign it would have made $350m. Marketing campaign was the worst for a big studio movie since John Carter. They played the plot too close to their chests, hoping people would be intrigued by a mystery, but instead it failed to capture what the story was about or give the movie a hook.
It most certainly is a feature film. especially back in 1921.
Any film above 40 minutes is considered a feature film for awards and festival consideration.