I thought the same thing while watching. I liked that it took its time and took its material seriously; as you say, it speaks to confidence in the filmmakers’ vision.
A big part of why it feels like a real movie is because Wakanda feels like a real place. I know a lot here have compared it to Asgard but that doesn’t scan for me at all. I can imagine what Wakandans’ of various social positions lives are like. Can’t do that at all for Asgard. Wakanda is also multicultural; Asgard’s just like 500 people who believe in the same things and do the same things.
Even the excursions outside of Wakanda feel like real places, which is untrue of many Marvel films (they’re getting better at that, though). Oakland and Busan are grounded in a couple distinct characters.
To me, Wakanda is more fleshed out than great fictional settings like Mos Eisley and Gondor. It’s a step or two below Hobbiton.
The parts of the movie that set up Wakanda and the relationships between the characters are the strongest for me. I love the slow build in the first two-thirds. But Killmonger is dealt with too quickly. I think they should have saved him for the sequel and had him defeat T’Challa at the beginning instead of over halfway through. The movie truncates Killmongers’ regime so it feels like neither T’Challa or Wakanda are ever seriously challenged.
For me, the first two-thirds of the movie are the best Marvel movie to date. But since the resolution to the main conflict is underwhelming I left the theater feeling a bit underwhelmed. Ragnarok stuck its landing, of a very similar plot to boot, so it still wins out as my favorite MCU movie. But Black Panther is close behind it.