This is so me I could have gotten blackout drunk, written this comment, and forgotten about it; dub-con is a huge no for me, sympathetic rapists are the BIGGEST NO OF ALL TIME EVER. I need the border between consent and non-consent to be as clear-cut as the edge of a cliff -- which doesn't mean I can only read, like, forcible rape, but there has to be obvious narrative intent to portray what's happening as Not Okay. (htp does this so well: Bucky can be begging for it and yet it's understood on all sides that he doesn't consent.) But your last points about mindfuck and defiant victims are really interesting to me, because that used to be true for me too. In every other fandom I've ever had, I needed the victim to be defiant to the last. Even in non-sexual torture fic, I needed the victim not to break. And then Bucky came along, and... well. Those rules no longer apply. Maybe it's because he canonically did break, and there's really no way to suppose he would have had more than moments of defiance against his tormentors?

But anyway, I feel your pain. I can't express the frustration of reading a rapefic that's going great right up until the point that the victim and the rapist ride off into the sunset together, to the soundtrack of authorial applause.