They didn't stay true to Diana's origins at all. Not her true origins, anyway. That's not even touching upon the other numerous problems with the film and the way Diana was depicted. One glance at her Post Crisis/New Earth run and anyone can tell the big screen Diana is not even recognizable as Wonder Woman. The movie definitely was a step back. It's truly sad that those who shot back at Cameron failed to understand that.
Wonder Woman was great. Gal Gadot was great as Wonder Woman. It wasn't the traditional Golden Age Wonder Woman story, but I don't really want Wonder Woman joining a side show where her manager takes advantage of her and taking the identity of a crying nurse.
James Cameron's notion that beautiful women can't be powerful is pretty much wrong and sexist. And your notion that you can't recognize Wonder Woman in that movie means that you're not really watching it or you don't understand Wonder Woman.