The problem with Black Panther, what what I've gathered of what I've skimmed off the net, and seeing as he is characterized on EMH, is that it seems like if it came down to saving the entire world, or saving Wakanda, he would let the world burn to keep his homeland safe. Contrast that to Captain America, who I could absolutely see sacrificing the USA if it meant the other 6.7 billion people on the planet lived.
I see that as less "problem" and more "story opportunity".
That said, just on its face, a black superhero named "Black Panther" seems way blaxploitation to me, especially (unless I'm forgetting someone) being the first black superhero to get his own movie. The character himself may be entirely inoffensive, but that name just seems like baaaaaad optics.
It makes him hard to fit into the current Avenger's/MCU mold though, without turning him into an outright villain.
Not at all. Have some conflict that threatens the world, including Wakanda. BP helps out. Midway through, it turns out that Wakanda can actually be saved by abandoning the Avengers. It'd just be a variation on the "sacrifice the many to save a few loved ones" trope, and could totally be done in a sympathetic manner.
And it'd be nice showing off more superheroes who are a little more nuanced. Most of the MCU supes are either unambiguously good or unambiguously bad. You have a few, like Black Widow, who have complicated pasts, but when she shows up on the screen, you know which side she's fighting on. Even in Cap2, you never really considered that she was going to suddenly become an antagonist. And then you have... Loki, I guess, but even when he's being good you know he's still a villain.
This is one area where I think Fox's X-Men flicks have the upper hand - you have characters whose motivations sometimes align with heroes, but sometimes don't, and it makes for interesting conflict.
I'm prepared for A:AoU to shake things up a bit with SW and QS.
And you don't see any potential issues with the idea of the black guy abandoning the team to protect his own interests?
Not really? He wouldn't be the first black guy in the MCU, and every other one has been pretty bad-assed and unambiguously working for the greater good. My only qualm is in giving the first MCU film devoted to a black guy a title that has "Black" in it.