One of the things I notice throughout your descriptions, though, is that the sex is used in a sort of meta way... That is, it's not always integral to the plot, even though it's integral to the "experience" of the book. The sex is part of the author's attempts to shock or arouse the reader, or, in the case of the Moorcock story, to cause the reader to examine the cause of his or her arousal. In these instances, you say, the sex helps the author make a point, one which -- in terms of the Ellison story -- would not be made nearly as well were it rendered chaste.
So the sex scenes, in those books, are part of the author's direct communication with the reader. As opposed to the author telling the reader a story, and communicating via the characters and events. It even strips away the "narrative voice." In many ways, it's communicating through visuals -- even if the visuals are formed in the reader's mind. It's a direct injection of mood or emotion or tone.
They help shape the way the reader experiences the plot. If removed, the plot still unfolds with clarity, but not impact. (I'm going by your descriptions, not having read the books myself...)
Close... but not quite. And I didn't want to get into too much description of the way it's used, because that might spoil the story for anyone wanting to read it. No, they are integral to the plot, as well... in "Catman" the interrelationships between the various characters hinge on their views of each other as sexual objects, as well as in other ways, and their inability (for one reason or another) to connect to each other (husband-wife, father-son, lover-lover, son-mother, etc.), even to the degree that the sterility of the society drives some to sex with the machine... the ultimate joy for them, as it allows them to truly become products of their society ... yet it is ultimately dehumanizing and destructively addictive. The same with the Russ story: it is absolutely necessary to develop the conflicts that are are the heart of the story; is, in fact, an excellent metaphor for those very conflicts that lie at the heart of the book. Moorcock's ... I chose those elements to emphasize because, of all the books, that is the one that is perhaps most centered on sexuality ... yet it is treated as an aspect of relationships that looms greater and greater, and is itself a very strong metaphor for what is happening not only to them, but to the greater world around them ... the two reflect each other, and each helps you to understand the other, and why this society is fragmenting the way it is. The book simply wouldn't be, if it weren't for the sex in it, any more than it would without the location (which itself, both the city and the brothel, become major characters), or the violence of the civil strife outside the brothel's walls (yet which invades their lives in many ways, both subtle and overt). It's a complex and rich book, deceptively simple if read hastily, and definitely worth reading and re-reading. The Farmer story ... again, the sex tells you mountains about the character(s) involved, and is closely tied to one of the major pivots of the entire story; it also helps toward understanding the society depicted, and its effects on the individuals. "Prowler", on the other hand, uses its sexual violence (which, again, is absolutely pivotal to the story), to assault the reader's senses (just as it does the character, even though he is only being made to relive his own actions --this is Springheeled Jack, remember), but it also starkly underlines the society depicted, and without it the society simply would lack an enormous depth it is given thereby; as would the characters, and the points Ellison's making.
In none of these could you remove the sexual element and still have a story. It would be like removing large portions of each reel of a film, cutting it down from 2-1/2 hours to 45 minutes to an hour, and then still expecting the story (already extremely tight) to flow.
There are, as I said, plenty of other examples of good use of this element within stories, which is why I have no problem with sex, no matter how graphic, if it serves the purposes of the story and what the writer is saying (a lot of these stories, while excellent
as stories, are also quite intentionally allegorical, and some of the best written allegories I've encountered, frankly).
I'm curious... J.D., can you -- or anyone else, for that matter -- think of instances where the hardcore sex works in hard sf?
That one... I'm going to have to think about. I can't think of any right off the top of my head, as most "hard" sf is more centered on the theories, gadgetry, and the physical sciences, and their effects on the people, rather than about the "softer", sociological sciences, which are more open to exploring emotion. Perhaps the one that comes to mind is the New Wave take on Godwin's "The Cold Equations", "X", a verse by D. M. Thomas. I'll briefly quote Greenland's description of it (I no longer have a copy of the original to refer to, I'm afraid, it having disappeared -- along with quite a few other things -- during a move). In the verse, Thomas introduces sex to the mix as well, increasing the pathos of the situation where both characters are concerned. But:
Down the left-hand margin of the poem figures tick off the minutes to her ejection, and, as a kind of commentary on the story, another column sets out words spoken by a schizophrenic, Julie, as recorded by R. D. Laing --
I was born under a black sun. Everyone pretends to want her, and doesn't want her.... I'm a no un, a noun, a nun, a no one.... I wasn't born I was crushed out. You're leally lovely lifely life, you destroy me with a red hot iron, burn my heart out, cut out my legs, hands, tongue, breasts.... I'm wasted time ...
-- and so on.
As you can see, the imagery, even from Julie, is chosen to enhance the emotional complexity of the situation and crank up the impact of Godwin's original (quite excellent) story to an almost unbearable point, yet is done in such a way as to both pull the reader into what is happening, and distance them at the same time....
However, as that is from
New Worlds, and is a verse, you may not include that in your criteria. Beyond that one... as I said, I'll have to think about it; but I think it's less likely, for the reasons stated above.