The foreskin is the most sexually sensitive part of a man, so when it's missing, yes, that diminishes pleasure. Also, an intact penis has a moving part, and that changes how intercourse is experienced pretty profoundly. Also, an intact man produces a natural lubricant when turned on, so it's not all up to the woman to produce enough wetness. It feels different when one mucous membrane slides against another mucous membrane rather than to feel a dry penis rub againt a mucous membrane.

In Europe, circumcision is rare (except among Jewish people) and most Europeans are shocked to learn that American men are generally lacking their foreskin. My husband is Dutch. He could not believe anybody would want to remove the foreskin.

I could write whole books on this subject; I'm passionate about keeping minors intact.