I think a movie that is able to speak to a cultural or political moment in a significant way and is able to do so without preaching, is better than a movie of equal quality that has nothing to say.
The thing is, pretty much any movie worthy of Oscar consideration is trying to say something.
Black Panther was a good Marvel movie. I actually enjoyed Thor: Ragnarok a lot more. I felt Thor was a more entertaining and amusing super hero movie. Black Panther obviously dealt with much weightier themes.
But I guess I would say that as a "message" movie, Black Panther was just so-so. I agree with you that it had raised some difficult and timely concepts. I'm not sure it really dealt with them in an especially in-depth or profound manner.
What made it remarkable is that it was a huge-budget global blockbuster that was also a decent "message" movie and stands as a milestone for representation in the superhero genre.
There are better superhero movies than Black Panther, some of which have come out in the last few years, but none that also had the same sociopolitical significance.