I know a woman who has the same problems with sex as she ages, and her partner is intact.
I've talked about it with my Mom a bit. My Dad is intact, and she says they (now) need minimal lubrication (never needed it before the menopause), but that sex is never uncomfortable/painful.
This is in direct opposition to the stories I hear from my friends who are my age (in their 30's) and who need lubrication (and plenty of it) with their cut husbands, and who find that sex can be sore/uncomfortable (and consequently, they would just as soon give it a miss...).
Can't speak as a post-menopausal woman, but sex is never uncomfortable/painful/sore (my dh is intact), and we've never had to use artificial lubrication.
But aside from anecdotal evidence (which is all we can have, as no one has done any studies on this) - doesn't it stand to reason that cutting off part of the penis will negatively effect how the penis works?
Millions of years of evolution (or God, if you believe in special creation) designed the penis perfectly for its main function - sex and procreation. It's insane to mess with that - and there is no way you are going to come up with a penis that 'works better'. It might work well (especially for the 'luckier' cut guy who was left with more skin than your average cut guy), but it's never going to work the way it was intended to work, sadly.