I like the idea of characters' sexuality being influenced by the players' willingness to pursue them. I'm gonna be a little shit, though, and say it's 2020. People apparentely got into an uproar over female Mandalorian armor. Strong independent lesbian character turning straight because male would attract all kinds of crazies.
I remember a lot of people getting angry because you couldn't do that with e.g. Sera in Inquisition and suspect that was the likely source of a lot of the hate for her, which was often excused as not liking her "stubborn" attitude. I don't really see the point of influencing a character's sexuality though: that's not really any different to the playersexual stuff we have already. I'm slightly on the fence about the subject; using DA as an example, I preferred Inquisition to DA2 but I suspect I would've had a very different opinion if the only characters I liked were unavailable because it wasn't a thing.
What about the romances in BG 2?
I loved working to get Viconia. And she made you work for it, and, honestly, she really wasn't worth it.
Or the romances in KOTR2?
Where i am going is this. The characters you had romances with were made with a background, and were not altered to be playersexual, but kept as their core beliefs.
Now, I will go back to KOTR2 again, in this respect. in dialogue with NPC companions, you could open up hidden classes for them.
So you had two ways to play the game... either let them level up in their base class, or through relationship points, open up jedi classes for level up.
It basically meant a drastic change in the characters in some cases. But it was rewarding.
That is where I am going with this.
Lock the options if you are not the right class/gender/race for it, or if your stats aren't right... or make it a SUPER high DC to achieve, and it is something that is completely shattering to the core NPC companion, but open up the option if Larian feels that strongly option should be there.
Don't just make it a given.
This also opens up the replay value. Roll a new toon for new options. THAT is the core replayablity from BG1 and BG 2. "What happens if I am this thing , at that place there, doing this thing?"