1: They made their villains interesting. I always say you can't have a good movie/book/show without a good villain. So with villains like Gorr, Loki (even tho he's an antihero now), Ronan, Nebula, Ultron and so on you are able to like these villains because they have interesting personalities. They're not just "Oh I'm bad because, well I'm bad." They have motives, pasts and good traits as well like all villains need.
2: They didn't try and redeem a thousand characters. Honestly I don't really care for redemption arcs because if you're bad you're bad nothing more to it. (I also don't like them because they're overused) Nebula kinda got a redemption arc but her character is very complex so it's hard to tell. Loki went from villain to antihero so I like that they didn't make him 100% good, makes him even more lovable to me! And Ava Starr was never really a bad guy anyway. She just did what she had to do. So I'm glad Marvel took the right path with redemption arcs.
3: Their heroes aren't overindulged with supernatural powers. I've noticed with a lot of superheroes they tend to push the agenda of supernatural powers. I'm glad that Marvel took the brave path and had heroes with more unique, human like powers. People like Natasha, Clint, Steve, Bucky, Shuri, Peggy, Tony, Sam, Val and Scott all are human but with special training or abilities. I think this allows these characters to truly grow and be better since they don't rely on these otherworldly abilities and they are true to themselves. Tony, Shuri and Scott are literally just normal people with techno suits. So my point is, I'm happy that Marvel made their characters more realistic and not power hungry, supernatural humans. Because I get tired of these magical powers.