I would argue that Changez is a strong character. He leaves his home to travel halfway around the world, alone and as a fairly young man. He gets into an ivy league school and earns top marks throughout his education, despite having to hold down jobs in order to earn money while he studies. After Changez is hired by the Underwood Samson firm, he learns quickly and begins to excel in his field.
However, as he begins to realize that he has some serious ethical qualms regarding America and American values—specifically regarding the country's interference with other countries abroad and its economic policies—he is not afraid to reevaluate his decisions. Further, he does not cower when he is faced with prejudice and racism but, instead, is prepared to defend himself and fight back. He returns to his own Pakistani identity to find himself and his priorities again, and he goes back to his home in order to lend his expertise and knowledge to his countrymen and women there. Even as he narrates his story, he is calm, despite the fact that his auditor—the American—is likely there to assassinate him (which we only realize as we put the clues together throughout the text). Changez is flawed and, at times, unlikable, but he is very strong.