I love your Brienne.
It would have been easy to make her plain unattractive, but you have made her look like a tough woman, with slightly manly features, with a subtle glimpse of a kind of beauty that would surely go unappreciated by medieval standards: she is big, has short messy hair and her skin is far from porcelain perfect. But she still has some hidden femininity hidden behind her broken nose and her manly armor. And also, her deep blue eyes, Brienne's most striking feature, that somehow look sad.
To me,this is the essence of Brienne, and you have captured it very accurately.