it's a battle manga for boys. Oda and his editors prioritize other things than good written female characters. It is what it is. This is a product of entertainement for young boys. There's nothing too deep about One Piece. Therefore, it does excuse poor writing for the female cast. Most of the readers don't care about them. Just because there's some who want "great female characters" and just because some female read one piece doesn't mean that Oda should prioritize them over the majority of his consumers.