It really depends. They should have their opinions and personality, but that doesn't mean they can't change if they see a role-model in you or you can sway them to your way of thinking. They shouldn't be emotionless or opinionless husks, but they shouldn't be static stick figures who can't be swayed. It really depends on their personality, if they are stubborn as mules and don't change their opinion even with overwhelming evidence, then that's their flaw.
The karma system sounds bad, I'd avoid it.
