Hey, I made the thread and even I know that Avengers is going to win worldwide, easily. Partly due to certain countriess just not wanting to see a movie starring a mostly black cast.
Domestically, people were seeing bp alone, with their moms, taking poor kids to see it, dressing up, etc. In America, BP has the support of the mainstream audience but, amongst the black audience it was a must see! People even agreed to not watch a torrent version of it.
Black Panther did ~640 million internationally, that is better than Hulk (128), Captain America (193), Ant Man (339), Thor (268), Thor 2 (468), Doctor Strange (445), Captain America 2 (454), Iron Man (266), Iron Man 2 (311), Thor 3 (538), Spider-Man (545), Guardians (440), and Guardians 2 (473)
The only MCU films Black panther didn't beat Internationally were Iron Man 3, Civil War, and the Avengers 1 & 2. Three of those are massive team up movies.
I don't see how you can look at those numbers and state people outside the US hurt its success due to a dominant black cast. People everywhere saw it in droves, it's just in the US it was staggering in success behind only Avatar and Star Wars Force Awakens in gross revenue. That's truly mind boggling numbers.