I can't honestly say I care even remotely about the "gender options" of the character creator, past the basics. Make me able to create both male of female characters and I'll have basically all I need in that area. But the more flexibility and options will be added to the actual character customization (look, physical build, voice, etc) the better.
For how I see it, the ultimate "litmus test" of a competent and flexible character creator would be the ability to pick a bunch of random popular characters from fiction/pop culture and being SOMEWHAT able to reproduce their equivalent in your game. Can I make expies of an Aragorn, Bruce Lee or Hulk Hogan? Can I have a big corpulent guy that looks like Kingpin from the Marvel universe? Etc, etc. *
it's not exactly my main concern about the game, but I would definitely welcome more options and flexibility than what was offered in BG3.
*NOTE: To be clear, I picked these examples absolutely at random as they were the first thing that passed through my mind and I don't hold any of them as a "must have" in the game. If you are going to comment something about not liking one of them let me tell you in advance that I simply don't care. If you are thinking they don't sound particularly tangent to the Divinity lore, that would be precisely the point.
Party control in Baldur's Gate 3 is a complete mess that begs to be addressed. SAY NO TO THE TOILET CHAIN