Downey Jr. was considered a gamble back in 2008 to play the role of Tony Stark due to his sordid past, but obviously that gamble paid off as the Marvel Cinematic Universe is one of the best movie franchises in existence.
Robert Downey Jr. recently said he doesn't think an Iron Man 4 will ever happen, but at least he offered if it does, he thinks they should go the villain route with Tony Stark.
Now Joe Russo, co-director behind Captain America: The Winter Soldier, Captain America: Civil War, and the upcoming Avengers: Infinity War movies, offer his take on what could happen to Iron Man when Robert Downey Jr. stops playing the character.
"It’s almost impossible to replace Robert, he’s the biggest movie star in the world. One close up from Robert is worth another actor’s entire performance, he’s incredibly gifted and insanely talented," Joe Russo offered to Forbes. "I think if and when he is done with the character, I think you will find that Iron Man might disappear for a while. I think the only way that you could reboot that character is to give a generational gap that would allow another actor to at least have a chance to redefine that character without the enormous spectre of Robert hanging over it. There are so many characters in the Marvel universe that can pick up the ball and run without it through the next phase or two before you need to see Iron Man again, frankly."
Robert Downey Jr. next appears as Iron Man in May's "Captain America: Civil War."