I think it was good the way it was. Though, according to OtherButtonJones, Coraline's parents helped her in the book.(?) To me, it would be a bit weird if her parents came to the rescue. Especially since in the previous scene the audience gets the impression that Coraline snuck out of her house, so that would mean her parents never realized she left. So, I think it would be a bit random if they just showed up to help her. Even so, how often do the protagonist's parents come to their rescue in movies? XD
Besides, if Wybie wasn't the one to save her, him and Coraline would probably have never formed a proper friendship. Sure, Coraline will most likely still pick on Wybie, but at least near the end she seemed to warm up to the idea that having him around isn't as bad as she previously thought. And you know, these movies have to have a happy ending and everything...so yeah. But still, I think that whole scene is great the way it is.
But what do I know, I still haven't read the book yet. XD