I wonder if we're perhaps getting our cause and effect mixed up here. I don't think it's unfair to say that the companion writing in this game is the best, most compelling writing in the game by a wide margin, compared to the main story. What if what we're seeing isn't a result of the general public just being dumb and horny, but rather them... meeting the game were it is, so to speak. They play the game and see that the character stuff is the most interesting and engaging and they think that it's because that's the part of the game that's meant to be important, the part of the game they're supposed to get invested in, and so they do get invested, and spread the game out to other people who enjoy that sort of game. So they're not disappointed by the poor main plot because they're coming at the game form the perspective that the main plot isn't really what the game is ABOUT, similar to how in Mass Effect 2, the main plot is there, but it's a vehicle to drive you to experience the various companion missions.
I don't think those people are dumb, but I've met the same crowds in the BioWare forums for the DA and ME romances, in the SWTOR subreddit a lot of posts are also about the romances. It seems to be one of the most popular features in crpgs and the devs cater to that. I personally don't care much - I'm not offended by sex, but I don't need it in my games. But I would like, if there would be a bit more balance between fixes for story issues and fixes for companion issues. So far it looks, like companion issues are the main priority - at least in my humble opinion. As I said, I love the game, but I think, it would be nice, if they stop catering to every romance whim and start looking into the story stuff. And yes, most companions are written very well, they have good storylines and you can luckily see them even without romancing them.
"We are all stories in the end. Just make it a good one."