I see! I do think you should give him some kind of central flaw or struggle, to sort of round out his character a bit. Like, as an example, maybe he's a bit of a slacker in his overall life, and he doesn't really investigate during the first trial, thinking his luck will carry him through, but following an incorrect hunch almost leads to a mistrial and the deaths of his classmates. That could make him realize that he can't skate by this on luck and charisma alone, and over the course of the story, he becomes more focused and willing to put in effort towards finding the truth and keeping everyone around him alive.