Sure, a skilled shot with precision hits killed deer, but it was often "iffy" as to ethical kills without wounding.
I've seen kids get so excited they had to ask which end the head was on
This question is going to come off as flippant. Its not intended to be. It is intended to be illustrative.
At what caliber does a bad shot become a good shot?
What caliber overcomes the second concern of a hunter not being able to tell what end of the animal the head was on?
My point is... these are not concerns that any caliber is going to overcome. .223 or .375 Holland and Holland are not making up for a lack of skill or knowledge