Peter,
Good observation/question.
I also wonder if this question is different for different skill levels. For instance, the 17th at Sawgrass may be an easy 3 or 4 for me, but it might be almost impossible for my dad. The 9th at Kingsley, while having eaten my lunch on several occasions, is usually a 3 or 4 on my card. But, for golfers who can hit it anywhere and have trouble with short recovery shots may pick it up after they run out of fingers to count on.
So, I think the question would be better clarified, for me, thusly:
For better golfers, which course's par 3's are least likely to yield birdies and most likely to yield bogeys or higher?
Joe