Avengers: Endgame saw the retirement of many beloved MCU actors and their characters. With Tony Stark and Steve Rogers now gone from all films from here on out (probably), it's time for a new character to take the lead. Many heroes have been speculated to lead the pack going forward, with theories suggesting who will be the most important player in Phase 4 and beyond. One of the newest theories from Screen Rant believes Scarlet Witch/Wanda Maximoff is going to be a crucial, if not the most crucial hero in the immediate future.
In addition to having her own series on Disney Plus, Wanda will also be appearing in the upcoming Doctor Strange in the Multiverse of Madness. The character was more of a supporting Avenger in the last several MCU films, and now might be the time to expand on her story and the true depth of her powers. Most of this new theory is based on one of Scarlet Witch's ability to warp realities, which hasn't been featured in a Marvel Studios film thus far. This could be one of the most important plotlines in the second Doctor Strange flick, as well as WandaVision.
The tease of the new series has Wanda and Vision living in the '50s as a happy couple, a nod to a different reality. Perhaps Scarlet Witch created this reality herself so that she could reunite with her love who was killed at the end of Avengers: Infinity War.
She could also open up the multiverse in Doctor Strange 2, setting up storylines for years on end. This would single-handedly make her the most paramount player in the MCU, as none of it would be possible without her. Opening up an alternate reality could be the way the X-Men are finally introduced into the universe as well, Screen Rant believes.
With such grand abilities, it's no surprise that Scarlet Witch is expected to be one of the most important heroes in Phase 4. Her powers have merely been touched on, and she will likely learn more about what she's capable of moving forward. There is always an ongoing debate about who is the most powerful being in the MCU, and a lot of this is based on what these characters can do in the comics. Generally, fans argue between Scarlet Witch, Captain Marvel, and Thor. All three of these heroes are still very active in the MCU, and future stories might finally provide an answer to the debate.