Ditto thermal issues, radiation issues, and so forth.
I disagree that the thermal issues were already known. The thermal environment on the moon is quite different from low earth orbit.
The two are the same in that approximately one hemisphere is black sky, which is essentially at absolute zero, with a 0.5 degree diameter ~6000K sun (sometimes) illuminating you. But the other hemispheres are vastly different. In earth orbit, you're exposed to an earth with a relatively uniform (day and night) effective temperature of 255 K. On the moon, you're exposed to a surface with a huge temperature range, from extremely cold (~95K) in shadowed areas prior to sunrise to ~390K (120C+) in areas normal to the sun. This was a significant design consideration for the CSM, which had to radiate the right amount of heat above lunar surfaces at all local times of day.
The suits were designed to insulate the wearer from as much of this as possible, but they weren't perfect. I know the Apollo 12 astronauts, at the least, remarked that they felt warmer on their second EVA than their first. They couldn't understand why this should be so, so this argues that their perceptions were real.
As for radiation, it
was closely watched at least during the Apollo 11 EVA. A conversation on the flight loop (surgeon?) asks for more frequent dosimeter readings so they could establish a dose rate, since they didn't have a rate meter. The numbers were too low, though.