It seems Mr. Howard was replace because of money issues (he wanted more money, Marvel Studios didn’t want to pay him more money so he bounced).
It’s common practice for stars to get a bump in salary for a sequel but according to Slashfilm, Marvel has been extremely tight with their cash.
While I did like Mr. Howard’s performance in Iron Man, Mr. Cheadle is no slouch. Here’s hoping he can pull off the role.
It’s been rumored that director, Jon Favreau plans to introduce War Machine in Iron Man 2. War Machine is a suit of armor similar to Iron Man but with Jim Rhodes at the controls. So look to see Mr. Cheadle rocking the stainless steel suite.