If I play one game as a woman romance Wyll then play another as a man romance Wyll and the game does nothing to recognize this it forces me to question the verisimilitude of Wyll's character.
On this point we absolutely agree! The game needs to do this
Well, and do more than just flip flop some pronouns and otherwise not acknowledge the differences in the general dynamic that it would cause... in fact it seems everyone agrees on this part at least. It does cause differences, and the game, if it wishes to be seen as doing this well, has to acknowledge those and change in subtle ways in response to them, without making them the dominating feature of the game.
A character that doesn't act, respond or treat you any differently with this flip needs to be established in advance as a person who is open to all things and not prone to it.. and even then, there should probably be small differences here and there regardless, because no real person is 100% unilateral in this area.
(Because, let's be honest, at the very basest, most ground-level point, sharing your body with another woman is an intrinsically different experience to sharing it with a man – no matter how without preference you are in your tastes. They're different experiences at a mental and emotional level, not just a physical one; one is not 'better' than the other, but they are very much different... and from that, differences spring up and filter into everything else around them naturally. It's normal and healthy. I assume without personal knowledge that the same is true from the male direction too).
For most others the differences need to be even more clear, especially around characters like Wyll and Gale, whose backgrounds set up likelihoods and expectations which, when they turn out to be broader than anticipated, absolutely should have conversations attached to them.