but everything about the title and every piece of artwork most definitely implies romance.
The title, as I've mentioned before, doesn't imply romance, not between main chars anyway. As for the artwork and main page feature list - how old are they? Feature list, I think, was made at the time when main chars had their old backgrounds. Now they have completely new ones and can even be of the same gender. Same gender "original sin" doesn't quite fit into common perception, no?
Doesn't matter what they intend with the story because they very much intend to sell the perception of the game at the very least having a romance option. You have to be blind and stupid to not see the very deliberate connections they are making with western culture. And if you really want to talk about older artwork for original sin, the female used to wear A LOT less clothes, with some more boobage showing(which is all fine with me) but it was due to massive player complaints they finally put some clothes on her. If you are seriously trying to argue they weren't intending to sell the idea of sex/romance you are fooling yourself.