As I stated in my feedback, personally I found npc sexuality too fluid. So long as there are some options for people that are interested in romance arcs of whatever persuasion, that should be sufficient and I would think it should kinda be written into the character in question (eg npc X likes guys, npc Y likes girls, npc z will go either way in the right circumstances etc). I feel that's more true to life.
An alternative way of running it would be for the npcs to be flexible but there are certain steps you have to take/signs you have to give/dialogue options that have to be chosen in order to unlock either homosexual or heterosexual romance with them.
At the moment it's a free for all even where you've shown absolutely no romantic inclination of any sort.
Anyway, I'm not into romance in a big way and don't think it's anywhere near the top of the list of issues to be addressed.
