I doubt Wonder Woman would do big business. They tried with Green Lantern and before you say "well, Green Lantern sucked" ... it doesn't matter that it sucked because the opening weekend didn't even do great business and that's for a film that was in 3D.
Lantern and Wonder Woman would both cost a lot of money to do correctly, especially Green Lantern would need millions in special effects and like it or not he is not that big of a character in the mainstream to warrant a $150M+ budget + advertising. They would have to do it on the cheap and then people would complain because it "looks like shyt"
Listen, I'm more of a Marvel stan than DC and even I will admit that most of the solo movies in the Marvel lineup have been average or worse. The Iron Man sequels were a joke. Thor has been average at best. The love story between Natalie Portman and Thor has been terrible and they have no chemistry. Only Captain America has a great track record. Everything else is leading up to Age of Ultron and even then they haven't done a great job with the build during Phase II.
DC does not need to follow that plan to be successful. Everyone knows Batman and his origin and the side characters... I mean they can still introduce them in these movies. Hawkeye and Black Widow were never given solo films so why should the DC side characters need one?
Only guy I would like to see as a solo joint is Flash.