I think this hypothesis is different from your reasoning claiming that clit positioning is a "useful defect" in that it claims that clit's positioning lost relevance altogether, so it is neither bad or good. What matters in reproductive success is not direct stimulation of the reproductive organ itself (especially the female organ), but the ability to produce sexual arousal by alternative means - stimulation other erogenous body parts, as well as culturally defined behavioral cues.
Wojtek
^^^^^^^^
The argument that c. stimulation does not enhance v. sex has not won the day yet, because the c. stimulation causes v. lubrication. V. lubrication is a pretty good sign of enhanced v. intercourse, and preparation for v. intercourse. C. stimulation enhancing successful v. intercourse would imply natural selection for females with c.'s.
Also, multiple orgasm is possible. The orgasm had from stimulation of the c. could create general arousal and receptivity for v. intercourse , again a natural script for selection for the c. In other words, being turned on in general could create greater receptivity to v. intercourse. Females could even stimulate the c. themselves in order to make themselves more receptive to v. intercourse. C. could be a natural lubrication "button".
I'm not going to get much into the v. orgasm/pleasure issue, except to say the stats from the one study can be interpreted as overwhelming majority of females have physical _capacity_ for it, which projected back tens of thousands of years in a non-male supremacist social context would mean something quite different with respect to receptivity to v. intercourse.
Evolutionary/natural selection explanation of the origin of the c. is not an explanation of "everything" . It is an explanation of "one" thing. Any trait that increases likelihood of having fertile intercourse ,and therefore improves differential fertility "score" is _very, very_ likely to be explained by a natural selection hypothesis. Differential fertility is even more important than differential mortality in impacting fitness. Any trait that increases fertile intercourse is very likely to have arisen through a natural selection mechanism, unlike any and every other trait that doesn't impact amount of fertile intercourse.
In other words, c is unlikely to be a Gouldian spandrel trait.
CB