2. Robert Downey Jr's Iron Man/Tony Stark
Arguably, there has never been an actor more valuable to more franchises at one time than Robert Downey, Jr. His first portrayal as Tony Stark in 2008s
Iron Man almost single-handedly made the title character a breakout hit. Once known mainly to comic book readers, the title character fast became a mainstream icon, replacing Spider-Man on the t-shirts worn by toddlers and grownups alike. The casting of Downey was absolutely spot on, as his personality in interviews does not appear all that different from Tony Stark. Both ooze self-confidence, charisma, and hilarious wit. It has been noted several times just how many moments of Downeys performances as Stark have been improvised, taking the character beyond what the script held for him. The success of
Iron Man propelled the Marvel Cinematic Universe from a great idea on paper, to a marketing and distribution strategy that could actually be executed. Even with
The Avengers success, the MCU runs through Downeys Stark. Captain America is the field leader of the team, but Iron Man is its true rock star, its front man. It is for that reason, among others, fans are quite nervous about all of Downeys recent comments about superhero retirement. Marvel Studios President of Production Kevin Feige has previously confessed plans to recast Tony Stark once Downey hangs up his helmet for good. Feige likened the role to James Bond, believing the studio can recast without a full on reboot. Having an expanded crossover universe makes rebooting prohibitive anyway. Marvel is going to have a very hard time in finding someone to fill shoes that seem custom made for Robert Downey, Jr.s feet. The studio will have to hope it can persuade Downey to return in
The Avengers 2 and
The Avengers 3, even if it means skipping out on a Downey-starring
Iron Man 4. At that point, deals with the other actors will near their end and most or all of the Marvel Cinematic Universe can make a clean break.