*Smug Brienne look*
I still haven't tried Brienne content but most if not all the players seems to love it.
And when was the last time Brint got anything? He's not even involved with the family subplot on his end.
Genderswapping is just a lot of work to make a character appeal to the opposite fanbase of the original for basically no net gain.
It then either stifles future development of the character as a whole (this is what's going to happen to Berwyn I'm pretty positive, don't expect any more large chunks of content for him/her ever again after this one) or one side gets neglected in favor of the other (Brint/Brienne).
It's a waste of time. Not to mention all the examples of it in this game are/will be male to female, giving the fanbase that already has
by far the most content even more and taking it away from the side that already is lacking.
And I'm not even a fan of male content, but I can recognize the inherent unfairness when I see it.
Just make a new character. Unless the character really leans into the fetish of being the opposite gender (and in all of these games basically none of them have) it would accomplish exactly the same thing.