By now the majority of Marvel Studios fans should know there are separate Phases connecting the movie universe story arcs and each Phase ending with an Avengers film.
Phase 1 was the origin arc ending with the Avengers coming together to fight off Loki's invasion, in The Avengers. Phase 2 is currently ongoing and it is ready to close out with next summer's Avengers: Age of Ultron. Then Phase 3 begins with Ant-Man, followed by Captain America 3 and most likely a Doctor Strange movie, plus Thor 3 and other unannounced films. The remainder of Marvel's Phase 3 plans are still unknown but most of it (or all of it) should be revealed next week during the studio's 2014 Comic-Con panel.
Meanwhile, Marvel's publishing side has already announced some major changes over the past few days. The first big announcement, which was and is still being highly criticized on social media, is that Thor is no longer worthy and a female is to become the new God[dess] of Thunder. Last night, on The Colbert Report, Marvel's Chief Creative Officer Joe Quesada announced there will be a new Captain America and it will be Steve Rogers' longtime friend Sam Wilson (a.k.a. the Falcon). Today, there is even more criticism directed toward Marvel because of the change to Cap. Both new comics will be able this fall.
In order to stay out of the surly debate of a female Thor and a black Captain America—it's not like these changes will be permanent in the comic book universe—there is the elephant in the room regarding what this could mean for the future of Marvel Studios' universe after Avengers 3, in Phase 4 and beyond.
By the way, Tony Stark is changing his Iron Man armor to something like Apple or Google would build as an Iron Man suit. Stark will let his darker side and ego run the show with a new suit and in his new Superior Iron Man comic title releasing this fall.
(This is where some speculation starts and this is just one guy's thoughts.)
In the Marvel Cinematic Universe and after Avengers 3, there will be actors whose movie contracts are fulfilled. Chris Evans, Chris Helmsworth and Robert Downey Jr. are the biggest names who will no longer be locked into a Marvel Studios contract. When you consider this fact—obviously they can all renegotiate new deals to player their respective hero roles longer—it seems to align with how Marvel is changing up its comic book heroes this fall. Marvel Studios' three main heroes (Iron Man, Thor and Captain America) will no longer be under contract after Avengers 3 so the studio may need to make changes to its big screen heroes as well.
Some fan will state how actor Sebastian Stan's 9-picture deal means he'll don the mantle of Captain America when Evans' contract is up. And this is a valid, logical assumption. However, there's a chance actor Anthony Mackie could become Captain America now. In this case, Stan could be a more heroic version of the Winter Soldier in Phase 4 and beyond.
For the big screen version of Thor, one way to bring more diversity into the movie universe and have a female in a leading role is to perhaps change Thor to a lady on the big screen too. Thor purists may hate it but those same people will still go to the theater and see a Thor movie, even if it was a female Thor.
Finally, when Downey's deal is up this remains the biggest mystery. Honestly, the logical choice it to have actor Don Cheadle assume the role of Iron Man and discard his War Machine / Iron Patriot armor. This is definitely the hardest change to speculate about.
Regardless of if you're a fan of the new Marvel comic book universe changes or not, you still need to consider the longterm effects on how Marvel Studios may see these changes. The potential for the studio to adapt these changes into the movie universe is definitely real. Just sayin'.
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