No, my position is that the parts which aren't removed have so much sensitivity that few can tell the difference.
Have you ever observed a total eclipse? I have, once. We all stood in bright, ordinary daylight until about ten seconds before totality. Of course, it wasn't really full daylight -- for more than an hour we were getting less than half of the usual dose of sunlight, then less than a quarter, then less than a tenth, but it still looked like an ordinary sunny day. Clear, crisp shadows, no "twilight" like you see leading up to sunset, just what looked like normal, ordinary sunlight.
I'm sure scientific instruments could have detected the dimming, and we could (using our eye protection) look at the sun and see how eaten away it was, but just looking around us nobody could tell the difference, until it was almost completely gone.
I suspect that the logarithmic nature of sense data means that, much as you'd like to believe otherwise, you experience pretty much the same level of sexual pleasure that I do. I suspect that whatever difference in "amplitude" that little bit of skin adds is a complete wash when the brain interprets it as "decibels" so you can know how loudly and how rapidly to groan "OGODOGODOGOD".
That's what the study claimed, and that's what brazenlilraisin said his first-hand experience confirmed ("the difference is negligible"). You'd think that on a skeptical website, evidence like that would count for something, but I'm still hearing "Sacre bleu, it cannot be".
So I'll ask again -- is there some reason you think retracting the foreskin prior to testing for sensitivity (I'm told this is its "maximum-arousal" configuration anyway) invalidated the experiment?