I just love when online armchair critics tell studios to "take a risk" fully unaware of how douchey it is to tell someone to do that when you have no stake in it yourself.
I've said it before and I'll say it again, Wonder Women's biggest problem in getting a movie is feminism. She's one of if not the feminist icon, so any movie she gets is going to be picked apart, scrutinized, and put under the microscope for hidden sexism. Too butch and man hating. Too Manic Pixie Dream Girl. Needing Steve Trevor to save her. Needing to save Steve Trevor. The outfit. Large parts of her standard origin. There's just too much that could be misconstrued out of context by people with chips on their shoulders, and until such time a Wonder Woman movie could just be enjoyed, not endlessly picked apart to determine how much it accidentally supports rape culture, any film maker would probably prefer to break dance in a minefield.
Guardians didn't have that problem because few know who these characters are, and fewer hold a firm attachment. I mean, I like the movie, but I was put off somewhat that Gamora, a character who in the comics could trade blows with Thanos and once decimated a UN military unit (complete with tanks) unarmed in less than 10 minutes, got reduced to someone that could be outdone by a normal human and needed his rescue. No preconceptions, no problems. On the other hand, while I wouldn't call Man of Steel a great film, so much flack came out of it not for the film, but that it didn't meet their preconceptions of Superman, and Wonder Woman would invite far worse.
Factor in that DC is having trouble getting these films right except for Batman, perhaps they should learn from Marvel and pick a lessor known to the masses character to start. Batwoman would get their female and homosexual characters out in one go. While I'd pity the actress, I always felt Zatana could do more interesting things than back up the league. I've got a soft spot for Stargirl from the 2000s JSA run. Same era, maybe tell the Hawk characters' story from Kendra Saunders' point of view (Carter being a bit stalkerish). If you don't mind monkeying a bit with Oriigins, World's Finest has a good incarnation of Power Girl right now (and it started in a costume without a boob window.) Or if you don't mind going dark, a take on Secret Six.
Just some ideas.