Jon Favreau clearly saw something in Sam Rockwell, because he eventually returned to the actor two years later for the role of smarmy industrialist Justin Hammer in Iron Man 2.
In the end everything may have worked out for the best; although Iron Man 2 is generally considered a weak moment for the MCU, Rockwell’s Justin Hammer is undoubtedly one of its best qualities.
If you ever wonder what Sam Rockwell’s Tony Stark could’ve looked like, then look no further than Hammer; apparently Favreau and Rockwell approached the villain by crafting him as a sleazy mirror image of Stark — albeit with less charisma and worse tech.