Question. Is the Black Panther always king? I know T'Challa and his father were both, but I could have sworn it was implied by T'Challa in Civil War that being both Black Panther and king isn't something that happens everytime.
What if we have a story where Shuri becomes Queen, and Nakia becomes the Black Panther. You would have this interesting dichotomy where the interests of the king and Black Panther don't always mesh, esp since Shuri would almost assuredly be more brash, and Nakia more restrained.
As for how they handle T'Challa's death, I am torn. Part of me thinks they will do it off screen. It is the simpler and perhaps safer option, but does create questions. How did he die? Was it a medical condition? Or does that hit too close to home with Chadwick.
The other option (and this is the one I think Coogler may be leaning towards knowing his strong instincts as a writer to ask hard questions) is the potential thematic advantages of having T'Challa die in the beginning of the film.
What if he dies in a similar manner to his father? Not necessarily in a bombing at a UN meeting, but on a more emotional scale; just like his father, he is at an event that revolves around allowing Wakanda to helps other nations, and at such an event he gets killed.
Just to give an example, perhaps after the Blip, T'Challa led Wakanda on a worldwide effort to help various nations with the sudden humanitarian efforts such an event would require. One such nation is Sokovia, who has had a section of its territory annexed by Latveria, a small bordering country that has emerged over the past five years.
T'Challa brings a large contingent of Wakandans to help the long ailing Sokovia, and when the reclusive leader of Latveria secretly issues his state police to infiltrate and assassinate T'Challa, the plot kicks off.
First off, this provides a thematic parallel to his father, who also died trying to open up Wakanda to the world (albeit in a more minor way). It immediately makes his death less of an afterthought that is just gotten out of the way offscreen, and makes it this dramatic event that kickstarts the plot. Shuri is left as the reigning Queen, and all the tribes mournfully decline to challenge Shuri/Nakia for the title of Black Panther.
Shuri immediately wants revenge against this mysterious Victor Von Doom (who's assassination of T'Challa immediately makes him a reviled villain), while Nakia and maybe Queen Ramonda are more measured, believing that's exactly the game Latveria wants to play.
It sets up the film as a geopolitcal thriller, and the whole "explore Wakandan cultures" aspect comes to the forefront when the various tribes argue amongst each other about what is the right thing to do. The consequences of Wakanda opening up also come to the forefront when Latverian agents infiltrate Wakandan politics and pay off royal and tribal leaders, creating a conspiracy within the Wakandan government.
Some of those political consequences are also very relevant to today, something Coogler did similarly in the first film when it came to the dangers of isolationism, amongst other things.