So, as we know, a character without flaws is a bad character. Typically, the reason why is that "a character without flaws is unrelatable". I actually have an alternative theory: Characters without flaws tend to be bland and predictable. For example: Everybody knows that Luke Skywalker isn't going to turn to the dark side. However, we don't know if Han will come back to save Luke in an emergency. There's some suspense going on with it. Though, this isn't to say that Luke is a bad character, he has his own faults. Keep in mind, though, that, according to my theory, people don't like your character for their flaws, but rather, for their moral triumphs over their faults.