Jeff,
I don't mean to argue semantics, but I can't give #5 at Merion West a "unique" adjective.
I think there are too many holes that 1) are designed such that the tee shot is better off in the rough than 1/3 - 1/2 of the fairway and 2) have a big tree on the direct line to the preferred driving area (the left rough in this case) such that only one type of shot shape is do-able (a draw around the tree on #5).
As you know, while I think the approach to the green on that hole is an excellent challenge, I am not a fan of the drive and what is required to achieve success for the second shot. If that big tree on the left were removed, and the fairway was widened to the left, THEN #5 would be one of the best holes on either course.
I regret to say that I have seen a lot more of those holes (on some pretty good golf courses, BTW) than I have "drop par 3's".