Personally I am always reluctant to recommend any character as definitive judge of armor. Brienne is certainly awesome and the representation of her by Gwendoline Christie has been amazing, but not without some questionable armoring decisions:
Really I think the bigger factor involved should be, “How will this make people look at the my character? What will they see?”
Brienne is but one of many possibilities, and part of what’s fueled the bikini armor trope is that creators got lazy and decided there’s just one type of heroine. A sexy one, with long legs, tight clothes and big boobs.
So rather than simply replacing her with a big butch one, we should be looking at exploring all the different kinds of badassery we can have. History of is full of badass women, many of whom used weapons and armor entirely different to Brienne of Tarth. Fiction should also be filled with similar diversity – hence Bikini Armor Battle Damage approves of many armors that Brienne probably wouldn’t.
Women of different cultures, different time periods and with different access to materials or facing different types of opponents. From the pages of history, for example:
This is before we account for things like different levels of suspension of disbelief, fantasy elements, etc.