"Proper" winning score?

Among the many reasons I love the U.S. Open is that the score of par takes on renewed significance. Any score in the red numbers typically is in contention, and rarely will anyone get close to the double-digit under par scores which are so commonplace for nearly every other tour event. Perhaps because I like seeing pros make bogeys or because a different scoring reality changes the players likely to succeed, I am always glad when even par can put a player in contention for a title.

But can there be too much of a good thing? Here's an article about the course hosting the PGA this year, with predictions that the winning score may be double-digits OVER par. I seriously doubt that will happen, but I'd kind of like to see it (if only for the reactions generated).

This all leads to the central question: What "should" be the winning score relative to par for a great pro event?