Cliff,
The holes in question are 8 and 15. 8 becomes a 520 yard straightaway par-5 if you play it to the 7th fairway, right of that forest. Taller trees right of the tee would probably fix that pretty easily. 15 is interesting because if you play it down 14 fairway it is a wide open tee shot, and a way better angle to the green. Conversely, if you play 15 down the correct fairway, you have a tight drive to a fairway pinched by bunkers and a bad angle into a firm green.
As far as 16, this is not the first time I have seen an Arthur Hills course with a par-3 that was simply too long to be considered a good hole. #5 at Stonewall Orchard rings a bell. I played the course in competition and to their credit they did have the tee moved up, but it was almost ridiculous from there even, particularly because it played into a ~30 mph wind and I found myself hitting 3-wood or even driver. I found myself looking back at the championship tee and thinking I wouldn't have been able to reach the green! Now if I were playing the course in a casual round, there is absolutely no chance I would move up a tee box to play the hole.
I'll agree that there are some great holes at NN but unfortunately for me a couple holes are enough to make it a stand out as "overrated" in my mind.