The film, which concludes a new trilogy of "Star Wars" films that began with 2015's "The Force Awakens", focused heavily on Daisy Ridley's character Rey and Adam Driver's villain Kylo Ren - with ex-stormtrooper Finn, played by John, and mechanic Rose Tico, played by Kelly, taking a backseat.
In a new interview with GQ magazine, the "Detroit" star criticised bosses at Disney for marketing the presence of a black character in the movies but failing to bring Finn's story to a satisfying conclusion.
"You get yourself involved in projects and you're not necessarily going to like everything," he says. "What I would say to Disney is do not bring out a black character, market them to be much more important in the franchise than they are and then have them pushed to the side. It's not good. I'll say it straight up."
Warming to the theme, he says he and Asian-American Kelly were also underserved by the failure to foreground their charaters' blossoming romance and stories.
"Like, you guys knew what to do with Daisy Ridley, you knew what to do with Adam Driver," he rages. "You knew what to do with these other people, but when it came to Kelly Marie Tran, when it came to John Boyega, you know f**k all."
"So what do you want me to say? What they want you to say is, 'I enjoyed being a part of it. It was a great experience...' Nah, nah, nah. I'll take that deal when it's a great experience. They gave all the nuance to Adam Driver, all the nuance to Daisy Ridley. Let's be honest. Daisy knows this. Adam knows this. Everybody knows. I'm not exposing anything."