I don't have the benefit of following all the series writers. I'm watching it more casually, without hunting down every shred of information about it. So Geoff Thorne's comments? Unless I can see it in the episode itself, it's not going to have a whole lot of impact on me.

Charmcaster cried when her father yelled at her. That still does not mean it's an expression of guilt. It's an expression of shame, which is different. Guilt is when you recognize your own wrongdoings. Shame is when someone else recognizes it, and you feel bad because of it. And she was never abandoned by Gwen and the others. She locked the door behind them. That's a major difference. She made the choice herself not to let them help her.

And yes, if there is a problem with the writer, then there's a problem with the character. If the writer can't get it across, then that completely changes the interpretation of the character.