To be fair, Beechen said it was an editorial mandate,
His complete and utter ineptitude took something that was bad (an editorial mandate to have Cass become someone that Tim faces because she's taken to killing villains) and made it much much worse.
He said in interview that he read the first few of her trades and the last few arcs of her book.
Meaning he's either a bold-faced liar, or he has the worst reading comprehension on the planet. There's no excuse for just how badly he fucked up every aspect of the character. You can't blame a complete and utter lack of knowledge for the character on "editorial mandate".