Thinking of all the books I've read lately that have spanking as random fun, I wander completely off the original topic...I like reading about some Dom/sub relationships, if I think they're done well, but I generally prefer the m/m relationships of that type. The submissive women in most books like that is portrayed as being even more of a doormat than the traditional romance heroine. Have the writers never heard of anyone being gleefully submissive? It doesn't even seem like the woman is enjoying it half the time, and if she is shown enjoying it, I'm usually wondering what's going on in her head for her to enjoy it. Characterization problems?
And for femme Doms? We're back to the overbearing and annoying, with usually bad D/s dynamics. It generally seems like she's just doing things on a whim, and is totally untrained. Meanwhile, the men have become the doormats, and take everything the woman says seriously, even if she's saying stupid and/or irrational things. I like those rare romances in which the characters give each other reality checks. Not necessarily in an evil way -- it can be gentle.
There are stories in which the hero and heroine work together. Stories where there's actual communication, and they work things out like grownups. I haven't given up m/f romance, I'm not squicked by it, and I don't usually rant about "girl cooties" being in a book, with the exception of books which have a woman randomly thrown into a male couple's perfectly good relationship. I don't think it's necessary to throw the woman in there at all, although I understand why it might be a fantasy for some women.
Will get back to this...