First Mr. Cabenza, you are a fool.
The differences between the two are not as large as might first appear. The Bethpage site is a fantastic one and even the flat terrain was used on holes 10-12 to create some of the best holes on the course. The Bethpage property is undulating, sand based and probably had more dunes and wasteland then the original Shinnecock property.
In my mind, the things they share are amazing routings that utilize the undulations. Amazing bunkering where the current edge might go to Bethpage but the original aerials show Shinnecock being quite a bit more dramatic and perhaps holding the edge. They share some of the absolute greatest uphill shots in golf. At Bethpage you have the short uphill approach to #2, the dramatic uphill approaches to #'s 5 and 15!!!!. At Shinnecock you have #'s 9 and 10.
Where Shinnecock has major advantages are
1- in the par 3's. The 11th is among the absolute greatest 3's in golf and to go with it are a bulletproof set of 3 others. The 2nd is a wonderfula long 3, the 7th perhaps the most difficult redan ever and the 17th a challenging mid-length hole. At Bethpage, the 17th is world class but #'s 3, 8 and 14 lag behind. Tillinghast built better 3's at many of his other designs.
2- THE GREENS! Simply put, Bethpage has some really dull greens. These include #'s 1,2,3,5,6,7,9,10,13.
Shinnecock wins the day here bigtime although greens like #'s 15, 17, and even 11 at Bethpage are teriffic. If Bethpage had a set that were all like these and especially at the end of a great short 4 par like #2 its rankings would be up in the top 10.
3- Another short hole akin to #2 at Bethpage would help with its variety and add to the enjoyment of the round and the strategic choices of the player. Shinnecock wins on this point as well.
4- Shinnecock has more varied weather and specifically WIND.
Bethpage has the possibilities to join SHinnecock among the worlds absolute best but it falls a bit short (In my opinion). Hope this helps.