Brace yourselves for a long 'un (apologies!).
T’Challa is a Be-er. @Decastell was right. The only thing is that there’s next to no clear examples of it because the movie is mostly OS, so there’s very little of that fish-out-of-water 'feel' to it. In fact, there are more clear instances of Do-er for both Killmonger AND T’Challa, so I can only assume that they’ve done a Bourne Identity thing where you have the ‘Black Panther’ T’Challa in the OS Throughline (who takes up most of the story) and the ‘Son’ T’Challa in the MC Throughline. Same player, two perspectives. It also doesn't help that for a long time, T'Challa has others to solve his problems for him (Okoye, especially, but also Nakia and Shuri step in on occasion), so we don't get a clear look at his preferred approach too often.
However, the two moments that convinced me that they’re intended to be Do-er/Be-er:
When Killmonger is brought before the council. T’Challa knows of Killmonger’s Wakandan roots, but he stays silent and internalises it rather than telling the council. It’s Killmonger that proudly screams his identity.
When Killmonger wakes up from the Ancestral Plane, he demands the heart-shaped herb be burned. One of the women says they have to keep it for future kings, and Killmonger chokes her to get what he wants.
The instance of T’Challa extracting Nakia mid-mission is one I chalked up to Do-er, but I think that might be the OS T’Challa acting. He does it of his own volition, just to invite her to the coronation. There wasn’t any kind of be-ing that I saw, other than the very brief ‘freeze’. But, again, it feels like T'Challa is a Do-er in the OS and a Be-er with his own issues.
Okay, so that first scene with T'Chaka is an interesting one. There's a lot I didn't remember. T'Challa says he's not ready to be without his father, but that he wants to be a great king, just like his father. The more personal moments in the story (such as when Nakia steps in as IC) include lines like "you get to decide what kind of king you are going to be." So it feels to me like he's deeply afraid of change. The death of his father and sudden coronation makes him want to be great, and the only way to be great is to be like his father -- which then leads to the inevitable heartbreak.
I also have a decent argument for Killmonger in Universe: he’s an abandoned Wakandan with royal blood (and Military expertise). That’s where his influence comes from, not just to T’Challa, but to everyone: he can’t be ignored because he’s not an outsider. He’s a legitimate choice for a Wakandan ruler, and someone with the proven skills and connections to do everything he says — unlike T’Challa, whom everyone (particularly W’Kabi) notes as “more of the same”.
I think the IC perspective is basically “our people’s future relies on us burning everything down” rather than “we need to open up”. The opening up/liberating countries/helping the oppressed stuff is DEFINITELY OS. Everyone has an opinion on what they should be doing -- which I think is where @mike.d's Isolation v Globalism thing is. There's a quad of Issues that came up constantly, and that was a really strong one.
There’s also very little RS. A couple of scenes here and there, but not a lot. There’s an exchange of dialogue before the train battle that lines up quite well with where I think the RS concern is, and that final scene between them is a great IC resolve, but the RS is really underbaked.
Also an instance of T’Challa’s change: at the beginning, he’s awkward just holding Nakia’s hand. At the end, he kisses her without a second thought. Not sure how I forgot that one. I think this is also supposed to be the Benchmark for the MC Throughline.
(A storytelling note: I still really dislike the big battle at the end with all of the drone stuff and the rhinos and the trains. The movie is so intimate and small-scale and then just turns it up to eleven out of nowhere and it’s just like… okay then. But I guess you gotta give the audience what they came for.)
As for concerns, I'm with @mlucas. The problems are consistently caused by Obtaining (or losing, in the case of the throne), and the quad of issues beneath is so, so strong:
Attitude: Tradition v Innovation ("Your technology is made by a child!"/Just about everything Okoye stands for)
Approach: Opening Up to the World vs Closing Oneself Off (Pretty much all of the council scenes are about approach, but there's a moment where Killmonger arrives and they're forced to defend their approach -- which is essentially to not get involved in world conflicts./Also a nice little bit: "Guns. So primative.")
Self-Interest: Protecting Wakanda's interests vs Using the Vibranium for Power/Influence (That's where you get everyone that's out for the Vibranium for selfish reasons -- money/power-- and the Wakandans trying to protect it as a valuable natural resource)
Morality: Looking Out for Wakandans vs Delivering Aid Around the World (Nakia best fits into this mold with her "We can bring aid around the world" and T'Challa responding with "We need to look after our own people first.")
I think it's here that you get all of the Mind-esque stuff, @mike.d.
Sorry about the lengthy post. I was just surprised by the sheer amount of stuff I had completely forgotten happened.