If Fazio would subsitute the words "very good" for "great". I just might agree with him. I have played some very good courses built on poor sites, some designed by Fazio himself. However, most of the courses I have seen on poor sites are mediocre to average, due probably to a lack of funds or talent.
On the otherhand, almost all of the "great" courses I have seen started with an excellent site. Very few of the modern courses I have played meet my definition of "great". Sand Hills, Pacific Dunes, Friar's Head and perhaps, Kingsley Club are great, and they all have wonderful sites.
In spite of his apparent fascination with the challenge of so-so sites, it has been my observation that Fazio's best courses were built on excellent sites. (I have not seen Shadow Creek.) World Woods, Galloway National, Forest Creek, John's Island West, and Members Club at Aldarra are among his better curses and they are all built on good sites.
I think that one of the reasons that C&C produce such outstanding courses is that they are very selective about which sites they will tackle. Fazio seems to be willing to take on any site if the money is there. If he didn't do it, the owners would find someone else, and who can produce a better product on an inferior site?