There are far more potentially offensive things in Mortal Kombat than this, and I think you're really reading too much into the video. While I do agree that video games and gaming culture in general need to look at how we treat women, and we can't just sit behind complaints the treatment of men and (which we tend to only complain about when the treatment of women is brought up... so how exactly sincere are those complaints, gentlemen?) and change nothing, this is not exactly the game to point out to address the issue. This is not the best example to raise the issue with, or at least the issues with the character are misdirected. I would look not at the origin story, but at her costume. Clearly she's meant to be not much more than eye candy for the player. When the games come out, I doubt we'll be caring so much about where Mileena comes from as what costumes she can wear when we play as her. But with most fighting games, that's to be expected. Most people don't really play fighting games for the story. It would be nice if more fighting games had more memorable stories, or we were at least given more information about the characters or the story was tied into the gameplay more, but not every fighting game can be a Blazblue.
But yeah, while I am all for more internal exploration into women and their portrayal in gaming culture, this character is not likely to benefit from that no matter what the outcome may be.