Considering how popular and successful Black Panther has been out of the gate, it's almost difficult to understand how the movie took so long to come to life. Why did the character spend so much time on the shelf? According to Black Panther producer Nate Moore, Marvel had been looking to make a standalone movie for the character as far back as 2010, but the first attempts at a script weren't working because the, then, standard format for introducing a comic book superhero just wasn't working for this one. According to Moore...
So, in 2010 we started developing a standalone movie, and with a very talented writer. We soon found ourselves falling into the pitfalls of an origin story movie. And that sort of familiar structure that just wasn't as exciting as we wanted it to be. So, we put it on the shelf for a while, and it wasn't until we were developing Captain America: Civil War??????? that we saw an opportunity to introduce the character in a different way.
Back in 2010, Marvel would have been knee deep in origin stories for the Marvel Cinematic Universe. The franchise had seen the introduction of Iron Man and the origin story movies for Thor and Captain America would have already been in production. It seems that doing something similar for Black Panther just wasn't working, but when Captain America: Civil War came along, Marvel realized it could do the Black Panther introduction there, which meant, as Nate Moore tells the Empire Film Podcast, Marvel could then follow it with a Black Panther movie that wouldn't need to be an origin story and thus could avoid the problems the earlier scripts had been having.
Needless to say, Marvel made the right choice. The studio could have pushed ahead and simply made a Black Panther origin story movie and dealt with issues to whatever degree was possible. Marvel had been finding its footing at that point and producing solid movies, so there's a decent chance the Black Panther origin story would have been good.
However, it almost certainly would not have been as good as the movie we got. Origin stories, by their nature, require a laser focus on their main character, which frequently means that successfully building other characters, villains, and the world in general, is quite difficult. Part of what makes Black Panther so good is the way that the film spends time making Wakanda feel real and giving other characters a chance to be fully realized. Such things would be quite difficult, if not impossible, in a straight origin story.
The one thing that probably worked in favor of Marvel waiting was the simple fact that Black Panther was not a widely known character by the non-comic reading movie fan, thus there wasn't necessarily a massive fan base waiting for the movie. That fanbase certainly exists today.
