I am starting to suspect that Piety DOES effect the Pope and his relationship with you. In my current French GA campaign since I took the 3 costal crusade provinces and had maxed out stats he has been real chummy. Italy and teh HRE have started wars with me and he has stayed allied to me. Also when the HRE attacked I retalliated and took Lorraine and Burgundy. I didn't even get a warning. I did not count up provinces but since I also hold England in addition to the outreamer provinces I suspect I was at the 2 to 1 point.