It always cracks me up to see modern fantasy and science fiction movies where petite women take on and beat male attackers in hand to hand combat. There are men strong enough to crack skulls and knock other men out with single punches, and men who can grapple so hard as to break ribs. Yet, I’m supposed to believe that training can give a 120 lb woman a fighting chance (hand to hand) against a guy twice her mass. That really is fantasy.
Every screenwriter wants to be Joss Whedon and I think Whedon has a fantasy of being smacked around by small women. :-)
In Buffy the Vampire Slayer he was trying to turn stories of the waifish girl in danger on their heads and made Buffy superhuman, but that doesn't explain every other female character he has ever written.