I live in a PCU level 4 (beyond version). A pendleton wool shirt and a wind shell has an amazingly wide comfortable temperature range between the two of them, I'll go from 90*F down to probably 40*, swap the pendleton for a PCU level 2 or patagonia R1 and you can get well below freezing.
I never used a windshirt in the PNW because it was just too wet, but here in CO the raingear mostly stays in the closet. I think the hunting crowd is much more open to thin, single layer softshells then traditional woven windshirts as they are perceived as being tougher and quieter.