Wonder Woman as some kind of breakthrough still doesn't make complete sense to me, but if the chattering classes in my Facebook feed are any indication maybe there's something to it.
I don't think it's a "breakthrough" of epic proportions, but it's a little something. Women as lead protagonist in action movies is a newish social/cultural trend. Like I said, the new Star Wars trilogy & Rogue One & Hunger Games etc. led by females (the woman who George Lucas hired to take over the Star Wars franchise for him is a woman...obviously an overt feminist, but she's a great role model too. She produced E.T., Back to the Future films, Jurassic Park etc in a highly male-dominated industry especially back then).
Movies are like any media, filled with propaganda and social agendas, good or bad.