While I do like the additional dialogue and character development that comes along with the romance options in Bioware games, I do have a big bone to pick with them. The main problem I have with romances in Bioware games is that there's no plot critical action involving them that occurs solely due to the romance.
For example, in KOTOR 2(YES I KNOW IT WAS AN OBSIDIAN GAME) cut content there was a scene where ol' whats his face(I havent played it in forever, so sue me - it was the sarcastic non-jedi guy you get at the very start of the game with the corny 'you look like an angel' line that makes fun of the phantom menace) sacrifices his arm or some such.
There should be some scene in the third Mass Effect where you have to make a choice(but ONLY if you've done the romance) between saving your beau and saving a ton of people. Or something just as big along those lines.
Actually I think I'll pop over to the Bioware forums and make such a suggestion.