I'm not sure I understand the issue mentioned by @mrfuji3 and @The_Red_Queen. Could someone shed some lights, please?
I have in mind the same logic that can be found in game like Dragon Age 2 were there is a male Hawke and a female Hawke.
Or how sometimes, there are movies were the main character was expected and written as a male but cast with an actress. Like Salt with Angelina Jolie.
And, in my opinion, it mostly worked. To me, it allows to break tired tropes, every now and then.
I am missing something? I legit would love some perspective on this.
In your example of Hawke, it's much more important to allow gender-freedom because Hawke is a PC for a past game. So inserting e.g., a Male Hawke into DAI would potentially mean that 50% of DAI players are now playing in a different continuum/timeline than they played DA2 in. Additionally, Hawke is a blank/neutral-ish slate whereas NPCs in BG3 have set personalities/goals/etc and are more tied into the entire game. Basically, a gender-swapped Hawke is close to a gender-swapped Tav than a gender-swapped NPC (e.g., Astarion/Lelianna). Also, Hawke is only present for a subset of the game, so the additional work required is limited.
And hmmmmm, while the ability to play as BG3 companions is possibly larger argument for allowing you to choose your own gender, it also weighs against that option by the increased amount of work. 5+ origin companions, for BOTH situations where they're a companion and the PC, accounting for their personalities & interactions with NPCs, throughout the entire game...it all adds up.