To the OP's question, I do think there is some fear on the part of WB executives to put forward a Wonder Woman movie. I think a lot of this fear, where gender is concerned, is unfounded. I think audiences have grown a lot more accepting of female action leads, in addition to female being involved in the action of male-led action films. A tough, capable female is almost in every male-led action film now.
Of all the female superheroes Wonder Woman is the most ready for the big screen. I was checking out her Encyclopedia and her rogues' gallery isn't bad at all: Cheetah, Giganta, Circe, Ares, Veronica Cale, Dr. Poison, Dr. Psycho, Genocide, Silver Swan, etc. And recently Hera. I could definitely see Ares, Hera, Veronica Cale, Giganta, Circe, and Cheetah being great adversaries.
I also don't think her back story and her mythological ties are any more confusing or convoluted than a lot of other superheroes. A good writer can pull the strands together into something cohesive. If anything, in this age were fantasy films and books are cool, it's a great time to try Wonder Woman. Thor is a good model for how to do it. Also the animated film DC put out a couple years ago would be another good place to look for inspiration.