I agree on the wind chill protection part, and while I think you are hardier than I am re cold and wet, certainly even with good rain gear we tend to get wet to a certain extent, but at least the rain gear as you say is keeping the wind chill thing at bay, and this is the big factor.

I figure that for summer tours, gear that keeps the wind chill thing is the most important.
My rain pants are fairly light and breathe fairly well, some North Face rain pants, so they work well for both aspects, and I do like that they go over my rain booties so my shoes dont get totally soaked.

re the shoe thing, once in France I had bad weather for a few days, cool and rainy, and no rain booties, so my shoes were soaked, my feet were cold, I was cold, I then got a cold, sniff sniff, and my shoes took a few days to dry out as the camping was damp and still not sunny.
So thats when I realized that my german riding partner's shoe rain booties were a good thing to look into, and have carried some with me ever since on trips.

my wife and I have done a week long supported trip many times, always in the beginning of aug, and on a few of them, the weather was not warm by any means, and one year in particular on the first day, it was cool to begin with, then started to rain, and then cooled some more and rained some more. We ended up with all of our rain gear on and continued on to the days destination, but there were loads and loads of people who just had either non waterproof thin jackets, or maybe a rain jacket but nothing else, so there lots of very miserable people, and many many that abandoned and were being trucked to the days end.
This was right beside the ST Lawrence river, which is cooler than most places because of the water staying cold all year round, which cools the air temp also.