I always find this sort of relativistic 'define good' comment somewhat irritating and pedantic - yes, we can debate the exact outlines of 'better' somewhat, but the gist of it is obvious.

In this case, reading a well-written novel is the fastest way to feel the same things as a person from a background different than your own, in a situation different from your own - and therefore increase both your empathy and your understanding of the human condition. What you do with that is up to you, but you'll have a hard time persuading most people that more understanding of others outside yourself isn't 'better'.