I don't think it would be to difficult to write LGBT relationships into RPGs, though it would probably be easier with party-based RPGs like Dragon Age, Mass Effect, etc., than open-world "Lone Hero" type games like the Elder Scrolls series. Hear me out: IF sexuality & gender identity (allowing for trans characters) were a part of character creation options, they could establish different character scripts for your party members, at least for the ones that are slated to be relationship options in-game. Say you make a straight character: Love Interest characters A, B, & C run with a complimentary script. Run a bisexual character, and the Love Interest List expends to A,B,C,D, and E, to reflect the same-gendered options who could run a bisexual or gay script. Same thing goes if you run a homosexual character. Not EVERY NPC's script would be altered to match your character's sexuality: Not EVERYONE has to have a script for any sexuality!
But the point is for the scripts of the characters to change, based on the nature of the romance plot. One problem I have with the romance plotlines in some games, for NPC's who can/will go either way, is that the script is IDENTICAL, whether your character is male or female. Liara's romance script, for example, was exactly the same, regardless of the gender of Shepard. Of course, Shepard's script was the same whether Shep was a guy or a girl: I get the "tough, military woman" thing for Shep, but the scripts REALLY shouldn't have been identical! And the same thing goes for including sexuality in RPGs: There NEEDS to be some variance in the scripts, which shouldn't be hard if you're able to choose your character's sexuality during character creation.
But the point is for the scripts of the characters to change, based on the nature of the romance plot. One problem I have with the romance plotlines in some games, for NPC's who can/will go either way, is that the script is IDENTICAL, whether your character is male or female. Liara's romance script, for example, was exactly the same, regardless of the gender of Shepard. Of course, Shepard's script was the same whether Shep was a guy or a girl: I get the "tough, military woman" thing for Shep, but the scripts REALLY shouldn't have been identical! And the same thing goes for including sexuality in RPGs: There NEEDS to be some variance in the scripts, which shouldn't be hard if you're able to choose your character's sexuality during character creation.