Eternals is not perfect but a progress. My rating is 3.5/5.
Positives:-
Stellar ensemble cast.Gorgeous locations & outstanding cinematography. Memorable characters. Interesting world building for Eternals mythology.
Negatives:-
Franchise building instead of standalone storytelling has took away the wow factor from the film. Story should have only focused on Sersi & Ikaris and other characters could grow around them but in order to give more focus on other characters, film's runtime got streched and somewhat subdued the climax.
Apart from it, here are the some reasons on why few people are upset from it :-
1. There are female leaders.
2. Majority of characters who lead, fought & won in climatic battle are female.
3. There is a LGBTQIA+ superhero.
4. Actors with asian ethnicity have important roles.