I think killing off a good character brings a sense of realism to a show. However, I don’t think it’s a good idea to kill off a character that the audience is emotionally attached to, or a character that actually has a purpose. Killing off Cera’s father wouldn’t be wise because he’s a great source of antagonism in the series. However Chomper’s parents would be fine as we’ve formed no emotional connection to them and they currently serve no purpose in the shows.
But then again, why kill off Chomper’s parents? What would be the point except to show realism? And you have to remember that it is a kid’s show. You have to be careful how you handle stuff like this, especially nowadays. People sue at the drop of a hat and there are more crazy parents today than ever before.