2023 feels like a distant memory in some ways. It was the year of the Barbenheimer phenomenon, the final season of Succession , and critically acclaimed music from Lana Del Rey and Olivia Rodrigo. Despite only two years passing, it feels like a long time ago, especially regarding superhero movies.
You wouldn’t understand some of Shang Chi without having seen Iron Man 3, though. Trevor has his own entire subplot which makes almost no sense without context.
They also do reference the clean slate protocol in Age of Ultron. By then, Tony has built the Iron Legion, and has started working on Ultron with Banner. Granted, it’s not necessary to understand the pathos behind the decision, but it makes more sense with the backstory. It’s like the central conflict of the whole movie, kind of the way Wanda searching for her multiversal children is for Multiverse of Madness. If you didn’t watch WandaVision, the movie drops a few lines of exposition to give you the bullet points, but it makes much more sense if you watch the show.
I was bummed they just kinda dropped the Extremis plotline entirely, but I’ve never thought the MCU needed more Gwenyth Paltrow.
And yes, the Endgame scene with Frigga would be extremely confusing without having watched The Dark World. I still think that was one of the worst films, but it is required viewing to understand the trio of Ragnarok, Infinity War, and Endgame.