Everyone points to Ripley and Sarah Connor as strong female characters, and while I agree, they weren't the draw for their movies. People went to see those movies for the Aliens themselves or the killer cyborgs from the future.
For those saying a heavy mythology based superhero movie can't be done... Marvel already beat Warners to the punch with Thor. I think eveyone would agree that Wonder Woman is much more popular than Thor.
I thought Thor and Captain America did as well as expected for superhero movies not named Batman. A decent Wonder Woman movie would make as much money. I doubt it would reach Avengers and the Iron Man levels though, those movies came out at the right place at the right time. Everything came together perfectly for them.