From what I'm told, Tim Robbins is going to be playing Howard Stark in an important flashback sequence that is going to set up the Avengers and Captain America films. Jon [Favreau] wanted to get a good actor because he didn't think the guy who played Howard in the last film could carry such an important scene.
I'm also told that HAWKEYE and BLACK WIDOW are definitely in Iron Man 2 and they wont be cameos either.
Can't carry such an important scene, Favreau? Did you not see him portraying "Mannequin" in the 1989 TV movie Stuck with Each Other? Or "Handman" (???) in a 1985 episode of Mister Rogers' Neighborhood? Or perhaps, more recently, you missed his turn as "Process Server" in The Young and the Restless.
Maybe Favreau will give Sanders a smaller part to make up for the change. I don't think anyone has been cast as Hawkeye's handman yet.