But they very clearly don't make Navarro out to be "average". She's buff, she's mean and she's been working in a male dominated environment for years where she has had to solve shit with physical force.
A later episode shows she shirks away from a guy she previously beat up, because he is now sober and with a friend. Her martial prowess is very realistically portrayed. They more or less did it as a David v Goliath thing. She knocks down a huge dude because he's drunk and he doesn't see it coming