If we could all take race out of our minds where it applies to Black Panther, there’s no reason why Panther could not or should not be Marvel’s highest-grossing franchise. He isn’t because neither Marvel nor comic book fans can neutralize the role race plays in terms of connecting with an audience, most especially with a character that literally has the word “black” in his name.
LOL no. You've actually covered why Black Panther doesn't work, though you've kind of skimmed past it & it has nothing to do with him being black.
The problem with Black Panther is two fold.
Fold the first: T'Challa...... The biggest hindrance to the character is the fact that the character is the freaking king of a foreign nation.
It also doesn't help that he is a huge Mary Sue. His resume essentially states "best at everything", but we never actually see it in play. On top of which the character has like a dozen different origins, some of which make less sense now then they did in the past.
For example, one of the origins includes a 4 leafed herb that can only be consumed by the royal family of Wakanda..... Except that their is no royal family of Wakanda, Wakanda was a trial by combat rulership model, not a monarchy.
An that's just one of the origins.
Fold the second is Wakanda. Wakanda is a Mary Sue nation, it's only qualifiers are "has never been conquered" (as long as you ignore the two times it has been successfully conquered), xenophobic autonomous nation-state & super technologically developed. It's never been develop as a character on to it's self, which makes the Black Panthers role in Wakanda completely useless.
This results in a character who has more power as king then he does as a vigilante, who puts on a costume to not fight crime in a perfect nation-state, because crime doesn't exist.
That's like if Bruce Wayne was king of the nation state of Gotham, where he puts on costume to not fight crime because Gotham doesn't have any crime, because Gotham is the most perfect technologically advance city on the planet & totally has no colorful villains to fight.
No one would purchase that Batman book either.
That's why the book is never about Black Panther in Wakanda.... It either takes place somewhere else, has swapped T'Challa out for a different character, have him be in it but be about someone else such as story, or takes place in a location that is NOT Wakanda.
There is never any consistency. You can't expect readers to invest in this character, when you give them nothing to invest in. The entire print run of the last 2 maybe 3 runs of this book were a scramble to find something to keep people interested: That's something that should be decided BEFORE you even pitch the book, not dozens of issues in.
Personally I think it'd be very simple to make Black Panther an interesting book, rather than just interesting in theory: A pure Black Panther book that I would read would require the mantle going to someone else, the powers to be well defined something to grow into & for Wakanda to be explored & developed as a real nation state, with real people in it & not always this shiny beacon of hope..... I want to see a Black Panther who really is the hero of the people of Wakanda, the people who are the dispossessed & destitute, because no society can exist without those people, because we can't all be rocket surgeons performing brain science.
An so here endeth my rant.