Not saying you are wrong, but IMO this take, if it's what the spirit of the rule is becoming, is bad.
A larger object making contact with a smaller object is naturally going to have an "overpowering" factor towards it and have dispersed impact to other areas. In this case, if Wilson's shoulder hit ZAR's shoulder as the first point of contact, that's on ZAR for not being a big guy. Shoulder to Shoulder checks are legal. You'll literally have to create a rule saying big guys can't hit little guys. There will need to be weight classes for what's allowed and what's illegal.
And yet, nobody feels the need to factor in relative height when discussing high sticks or cross checks to the face. How weird. Almost like it shouldn't matter.