I have to say I am really torn on this topic. I agree with those individuals who say that romances in games tend to be a silly add-on that adds little depth to a game, but does this invalidate the premise?
Whether we like it or not, romance and relationships are a massive part of adult human interactions. So to leave it on the proverbial cutting room floor in favor of dungeon delving seems to me to be leaving behind a significant part of the "why" of why people do the things they do. On the other hand, a mindless gift exchange for "favors" does not reflect the reality of these necessarily complex social interactions.
One thought on the topic: Charisma is a much maligned stat, and yet in Arcanum (where it was beauty) it made a huge difference in all sorts of player interactions. I think that if a player elects to make a knuckle dragging warrior (all dex str and con with everything else minimized) then romance and even civil discourse should take a back seat. If a player elects to make an intelligent, charismatic character, then it seems that this should effect how NPCs interact with the character, including how "attractive" they find your character to be.
Lastly I will say, as a combat veteran, that going through life threatening situations with other people tends to generate extreme emotional responses. I am not just talking about romance but in all aspects of social interaction. People you get along with become like brothers and people who annoy you or those whose abilities you do not respect become an object of intense hatred. The extremity of the situation generates an extreme social atmosphere, and often pushes people romantically towards or away from each other. I think that if we are to have a game that is seriously grounded in adult social interactions we ought not to leave behind such an essential aspect of those interactions.