Tom Doak,
I've never played Crystal Downs, but, Merion has more contour than Sebonack ?
I can't think of any greens at Merion that come close to the contour and slope of 's 1, 2, 3, 7, 14.
And, the contour and slope of the other greens at Sebonack are quite pronounced.
I think that one of the advantages of large greens is variety in play.
By "play" I just don't mean putting, but approaches and recoveries.
For example, the 11th green at The Creek is about 80 yards in length.
It's surrounded by water and gets a lot of wind.
Thus, the hole can be played with a wedge or a driver and any club in between.
That's variety and that's pretty neat.
A large green can also present an entirely different approach shot when the hole location is moved, and that's another facet of variety that's inherent in large greens.
Take # 3 at Sebonack and the difference in the approach when the hole is cut front right or back left.
Those locations call for different thinking, different clubs and different flighting.
Again, that's great variety, ergo interest.
The same could be said of # 17 and a number of holes.
That's not to say that the use of a small green, especially one that plays smaller, like # 5, doesn't have their place.
MeadowBrook probably has the largest greens I've played, but they don't have the pronounced contour you find at Sebonack and other courses.
I think one of the smart things done at Sebonack is the creation of a hybrid course, a combo of the white and blue tees for those where some blue tee holes may be too much for a golfer's game.
Approaching # 2 and # 3 is a daunting task as you distance yourself from the hole, therefore, playing the combo course and teeing off from the white tees offers the golfer a measure of relief while still presenting a significant challenge.
I could easily set up Sebonack such that no one would break 80 in 2013.