How is having a LI of those orientations taking away from anyone? There would still be a romance arc, and it would be available to all players. The only orientations that take options away are heterosexual and homosexual, since they are only available to one gender.
Honestly, if they'd just do away with the sex scenes, inject some fade-to-black in romantic moments, and be ambiguous about when / whether intimacy has ever occurred, they'd solve a lot of problems - especially if they added repeatable flirt / proposition dialogues ala DAO.
-- No more formulaic sex before the final battle scenes.
-- Affection / sex / whatever could occur whenever and as often as the player chooses.
-- Any romance could be asexual, demisexual, fully sexual, or full-on rabbits.
-- No having to deal with any issues around nudity in sex scenes.
-- It would be a giant step toward allowing different body models for the protag.
Of course, people who need to see everything play out on screen might not be too pleased about it, but the role-playing freedom would be enormous.