The release of Avengers: Endgame was really the end of an era for Marvel. Many of the characters had finished their stories and no longer had a role to play in the MCU, such as Captain America and Iron Man. Going into Phase 4, a lot of characters have been expanded upon or given new life, while in other cases, brand new characters and stories have been introduced. Most notably, the tone of Phase 4 feels different, and it distinguishes this era of Marvel from the previous ones.
Phase 4 feels more experimental, and it has the feeling of a newborn deer with shaky legs that's still trying to find its footing, similar to the way that the MCU felt at the beginning of Phase 1. The stories are interesting and fresh, but there's not a sense of unity yet, as a lot of the characters and stories are still separate and haven't had much of a chance to connect with each other. The biggest difference is the lack of a central character or multiple central characters, because it feels as though so far, Phase 4 isn't revolving around one or two main characters in the way that past MCU phases did. What does this mean for the future of the MCU, and is it a bad thing that the characters are presented more equally?
The first three phases of the MCU didn't necessarily have a "main character" in the traditional sense, i.e. a protagonist who is the sole point of view throughout the story with everyone around them serving as side characters. Rather, many characters were the main characters of their own stories, but two heroes, in particular, were always positioned as the leaders, and much of the main conflict revolved around them. These characters, of course, were Steve Rogers and Tony Stark. Their conflict with each other in the first Avengers movie is something that carries through the rest of the MCU, and they were always the main stories that the MCU kept coming back to.
This is obvious in Endgame alone, as it's clear that it was meant to be a conclusion for both of their characters, while other characters like Natasha, who also died in that movie, were not given the same main character farewell. They were always the main characters of Avengers movies, and they were always referenced in other parts of the MCU. Though they were just two parts of a massive universe, Steve and Tony were, for the most part, what that universe revolved around as the most major players in the game.
Phase 4 has launched full swing this year, and so far there are really no central characters emerging, though that might not even happen until after another Avengers team-up, if it happens at all. The closest characters to this might be Wanda or Doctor Strange, simply because whatever happens in Multiverse of Madness looks like it might affect the rest of the MCU going forward, and they're the biggest players there, but even they're not focused on in the same way that Steve and Tony were. It's hard to tell when there's no actual Avengers team currently, but it really feels like this phase of the MCU is less focused on one or two central characters and is instead trying to split its time between several of them.
Is this a bad thing? Not necessarily. This gives the MCU the space to explore a multitude of different stories without feeling like they need to tie back to any central story arc, and it allows for multiple characters to feel really important, not just a few of them. Having central characters makes the other characters around them feel minor by default, so this method allows the audience to recognize that all of the characters have equal importance in this world. It might be a nice change of pace to have Phase 4 be so vastly different from the previous ones and really set itself apart.
At the end of the day, that's what Marvel seems to be trying to do with the new phase. Rather than focusing on two men and their problems, they want to take a more wide-reaching approach to the MCU and focus on everyone's issues. It might be harder to tie together story threads without those characters that bring it all together, but perhaps a few characters like that will emerge in future phases. Even if they don't, having no central characters will definitely distinguish Phase 4 from its predecessors and make it truly feel like a new beginning. The MCU is often formulaic because they've figured out what works and they stick with it. In this particular instance, however, it's nice to see them deviate a bit from that classic formula that they've been using for years and years.