The other problem is that this would create more cases of "mutual rape" where two drunk people have sex, and either neither of them is responsible, or both of them are. The intuition that only the man should be responsible is common, but legally unworkable.
Changing the law is open to debate, but can't be done retroactively to prosecute this case. But this is easier to say than to craft into law. Should it be illegal for a woman to get drunk and have a one-night stand? I'm open to "yes," but that's the question.
Also, maybe outlaw group sex entirely.