I don't like this approach and it's never done well. By its very nature, it can't be done well because its entire purpose is not about writing engaging characters. It's about reducing them to different flavors of fuckability to cover as many player tastes as possible. People behave differently around and to other people depending on their sex (and race and background and social class, and the values of the society both of them were brought up in), and playersexuality removes that outright just so that no player feels "excluded" from experiencing their sex fantasy in a video game.