I would say it isn't impossible or even hard to make good female characters in gaming. (Ok, maybe "good" isn't the right word, but rather "safe.") It's just that you never hear them praised or demonized. Why? Because most of the time you don't even notice them, and a feminist who probably doesn't know anything about SoulCalibur outside of the boxart definitely isn't going to.
Let me give you an example: Mei Ling from metal gear solid 4. She was in the game (relevantly anyways) for like, 10 minutes, as the captain on a large vessel that was headed on a dangerous mission. Even though she was able to keep her composure and inspire her crew ultimately, you could tell that she herself was nervous as fuck the whole time. It was extremely believable, and it would've fallen completely flat if the character were male.
The thing about it is, she's not a particularly interesting character, and she doesn't draw attention to herself. What draws attention? Blatant fan-service characters and tough action girls. Naturally, if you're marketing or even writing something, you want your characters to at very least draw attention and be relevant to people's interests, and frankly, realistic female characters, or realistic characters in general don't always do that. Look at Kratos, Solid Snake, Marcus Fenix, Master Chief. Do they accurately represent what the male population is really like? No, but that's what makes them interesting. Characters don't necessarily always have to be fucking role models.
eh i could rant on this forever. Basically I don't even think the medium is broken. There are always going to be your bayonettas and alyx vances, and both have their appeal, which is why nobody notices the Elikas or Elenas or Faythes or Mei Lings or... well you get the idea.