The idea of legacy seems to be the overarching theme of the MCU’s Phase 4, and She-Hulk will look to push that concept. It would make narrative sense for Bruce Banner to appear in the Disney+ series, but a younger version of the character presents an opportunity to flesh out the Avenger even more. In conjunction with that, it also has the plot potential of establishing the dynamic between Banner and Jennifer Walters during their younger years.
Exclusively Reported by ‘The Direct’ that She-Hulk is set to feature a younger version of Bruce Banner. Marvel Studios is currently casting an actor around the age of 10 years old for the role.
That being said, the MCU is known for exploring family-heavy themes throughout the Infinity Saga, with examples such as the familial relationships between Tony Stark and Howard Stark, Star-Lord and Ego, and Thor and Odin. By exploring Bruce’s past through Jennifer Walters’ story, it gives the franchise a chance to flesh out his character and build on the overarching theme of what’s already been presented in past MCU films.