Actually, now I’ve thought about it more, the place I’d actually start if I were going to try to create a more “realistic†experience for trans characters would first be creating a world in which NPCs more obviously judge gender by appearance, which is not something that I’ve really seen reflected in games I’ve played before, which have tended just to go by the sex/gender the player picks at character creation and not worry about it further. In this sort of setting, suddenly having NPCs become sensitive to gender cues just for trans characters would seem weird and wrong. I feel that a world in which it would make sense to have NPCs respond differently to trans characters would need to be built from the ground up and would need to be one that cis characters would also experience differently.
For example, I’d start by considering how different races, species and cultures would perceive gender of races, species and cultures other than their own. I might, for example, have certain NPCs that would reliably judge the gender of individuals of their own race by appearance but would be more likely to get it wrong for some or all other species. There might be NPCs who for one reason or another, assume any elven PC they meet is female, or male, or just call everyone “they†and don’t try to identify a gender at all or randomly pick or even swap around, and some NPCs might ask if they’re unsure. I might even chuck some more randomness into it, and give each NPC who might try to establish a gender for a PC a DC, which might differ depending on the PC’s race and other factors, and let them roll to see if they got it right. I might then ask the player to specify how typical an example of their gender their character was for their race (regardless of whether that character were trans), perhaps as some sort of slider, and use this information to affect the probability of at least some NPCs of calling it right (most likely those NPCs whose gender norms were most like those of the PC’s race). I’d then create appropriate interactions for when NPCs got the gender of the PC wrong. None of this of course requires an actual trans PC at all, but once this world was created then it would seem less difficult to add them and have NPCs react differently to them because of their appearance without this feeling forced and strange. The player would just do exactly the same as for any cis character, and specify their gender at CC, choose the body type and other aspects of their appearance however they wished, and as for any cis character specify how accurate assessments of their gender by their peers was likely to be (or how accurate they wanted them to be, if they preferred their character to be misgendered less often).
I imagine ideally that there would be further options that we’d want to choose, but again these don’t feel as though they should be specific to trans characters. For example, pose and gait, as suggested by Blackheifer above, and how different armours/clothing would look on our characters (for example whether we wanted it to emphasise or create curves, or disguise them).
I’m sure there are some problematic aspects of the above that I’m blind to (in which case my apologies) and I think it would be a lot of work. So again it comes down to prioritisation and how much benefit players would get from it. But I do think that unless more fundamental enhancements to the game setting along these lines are made, any quick fixes to have NPCs respond to trans characters differently are probably going to feel unsatisfactory and uncomfortable, and the current approach of just using the identity specified by the player might be best.
