I don't think Morrison is really trying to say something new or interesting about feminism in his WW Earth One books, but rather trying to grapple with Marston's ideas, which virtually every creator since the 1940s has been trying to avoid like the plague in favor of more palatable notions of female empowerment. While I don't think Morrison's WW stories have been completely successful, I give him credit for at least trying to engage with the original conception of the character, rather than the more mainstream, and hollow, version that most people are familiar with.
Granted, I think he was more successful in his attempts to realign Superman to his original social crusader roots, even if that version didn't last very long either.