I would say underappreciated or even overdismissed, rather than underrated.
As a golf course it is a solid one with very few flaws, and occasional world-class inspiration.
I personally think that the 1st 5 are overrated.
#1 is a virtually unequalled transition/opening hole, transporting you from anticipation to mystery to spectaclular challenge. If there is a better #1 in the world, I haven't played it.
$2 is also superb. Great use of elevation to show the golfer that 350 doesn't necessarily mean birdie.
#3 is mediocre. Basically a drop shot par-3 to an island green, where the water is replaced by iceplant.
#4 is all-world, and we all know why.
#5 is OK, but RTJ blew this one. A little work from a shaper, and this could have been THE Redan of American golf
As for the inland holes, yes it is a bit reminiscent of Georgia or the Carolinas, but without the cooling breezes and with the anticipation of a post round restauration that will consist of proper cuisine rather than greasy pork and vinegar served by wenches in ill-fitting tops (hmmm. is that a pro or a con?).
#6 Very much a "You're not in Kansas" anymore hole. When I played it (mostly in the late 70's/early 80's) it was (from the back tees) a try to hplace a hard cut between the bunkers. When I followed Watson and Nicklaus one year and saw each of them seemingly effortlessly fly the right hand bunker, I knew that they played a game with which I was not familiar.
#7 I'll disagree with Andrew, and say that this is a very good golf hole. Virtually the same golf hole is #15 at Harbourtown, which we all seem to love.
#8 is very good. Seemingly wide but, very narrow if you are thinking strategically. 2nd shot semi-blind to a very complex skyline/treeline green.
#9 A weakness, in that without googling up a routing I can't differntiate betgween this and the 18th. All I can say about either of them is that they are workmanlike golf holes requiring skill and precision.
The back nine has some superb holes, and some very interesting ones. There are no "ho-hum"'s by my standards.
#10 has a GREAT vertical hazard in the tree in the fairway to the left which makes the hitting of a controlled low draw far preferred to the bomb shot irf you want to shorten the hole.
Can't comment on 11 (or 16) as they have been changed since I last played them.
#12 is the finest par-3 in the world, in that it was the site of my 1st hole in one. More seriously, it (and 15) are far better examples of a quality drop-shot par 3 than #3. A very good example as to how context tends to influecne architectural criticism.
#13 is a hole which grows on me in reflection and over time. It is simple--hit it solidly up a hill, twice, then 2-putt if you can. Pure golf, without the frilly knickers that so many take as "greatness' these days.
#14 is a brue of a Par-5 that will challenge all of the pros. For us mortal, it gives all soert of options for tacking our way to the hole. Kinda liek the 14th at the Old Course, no?
#15 is another cool drop shot hole, and the pond is very much in character with the topography.
#16, a great long 4. Looks a lot like #14, but you have to get there in 2! How you do it is up to you. That is golf.
#17 is a great short 3. even though (I think) it is not in driving range. Lots of angles off the tee and a superb green.
#$18--see #9 above.
'm getting tired and busy, but will jump back in if others so wish.....
Rich