Are you assuming that because he didn't go on a diatribe about his plan for economic stability, in a 2 hour comic book movie mind you, that he didn't have one? An MIT grad and an obviously intelligent and learned individual just decided one day, "kill whitey and all will fall into place"?
No, I think that's drawing conclusions based on a lack of evidence but not ignoring evidence that may suggest otherwise. A couple examples, in the first Iron Man Obadiah Stane wanted to kill Tony Stark and use his arc technology to sell better weapons. We don't get a scene where he verbally States his business plan but the fact that he ran the company for years makes it feasible that he had one. Then you have Loki who seemed to only want to be a king for the purpose of sitting on a throne being praised by his subjects. But there's nothing in the slightest that suggests that he had a clue on how to rule a city, let alone an entire planet.
My point in saying it's a 2 hour comic book movie is to say as great as the messaging was here, the pacing would have taken a nosedive if they went that far into Killmonger's long-term plan. What we know is that he planned on using United States tactics to create a worldwide Wakandan empire using what he learned in MIT and the military. What could he have learned? Look no further than Obama and Bush's plans on restructuring Iraq, Libya, Syria, etc. It starts with militarized action, then economic and political implementation.
