I think you missed the point. There is QUITE a difference between a character that merely reflects the PCs sexuality, thus their (non-discrete) sexuality plays no role in their personality or background, and a character that has their own sexuality (which may or may not be explicitly stated), which has an influence on their background and personality.
Right, there's a difference between Kaliyo and Ensign Temple for example. With Kaliyo, an important part of her characterization involves her troubled relationships with people, including romantic partners.
However, when a character's sexuality isn't a part of their characterization (Temple) I don't see the benefit of making them exclusive and not going the PC-sexual route.
If they want to make a character where sexuality is important to their character arc (i.e., if they wanted to explore issues with homosexuality in the SW universe...if there are issues with it) then they would need an exclusively homosexual character. Though, if they do that too much I couldn't take it seriously.
It seems to me that most of the current OGRA are PC-sexual as it is....they don't show indications of their heterosexuality beyond interacting with the opposite sex PC. Doc and Kaliyo seem to be the only exception I can think of atm, but I haven't played all the class stories.