I see your point, but TBH I feel more recoil from 3" turkey loads than I do from slugs. I think having an excellent recoil pad and mounting the gun properly helps a good bit. When I first started shooting slugs, I tried to mount the gun like I would a rifle. A week later I was still sore. Now I mount it like I do for any other shotgun load, and only feel soreness after a lot of shooting.
I suppose everyone is different.