"Opera and music in general makes you a healthier, more functional person if you study it, as in perform it. The stories about its power to heal are true. However "better" in the sense of more morally correct? Hmm. That 's tricky.
In some cases listening to specific music under controlled circumstances can have a lasting effect on the nervous system. It can improve the ability to express oneself, lift depression, aid in learning issues and much more. You can read the reports of El Sistema, and you will see that the future of those kids from this system have a better future than they would have without musical training. It may not lead to a career in music, but it has all sorts of effects of self discipline, academic achievement, a sense of belonging and commitment to the group and to society.
When people make music together, and I am speaking of classical music here, empathy is created by the act of breathing together and having to sense one another when we play in ensemble. We secrete oxytocin and abound deeply.
This is not true of rock, which has been shown to be mentally and physically draining.
Since empathy creates a person who is prone to act with some empathy, then I would say that to the degree this can be so, then yes, in some ways it does make you a better person.
Since singing is thought to be the best exercise for body and brain then there is some argument that maybe opera is better than instrumental music. I would leave it at saying that singing is more inclusive and health giving.
OK so will it make Dexter into an empathetic human being? No, because the real-life Dexters of this world have a piece missing in their brain that makes empathy impossible. Mind you, Dexter the TV show, has become very muddled. Either Dexter is faking falling in love, or he is not a psychopath. Both cannot be true. They are mutually exclusive. If he were real. He is not. So the writers are free to mess with the story. The reality is, once a psychopath, always a psychopath."