One (related) theory, penned by yours truly, goes like this...[from Routing the Golf Course]
"The most intriguing mystery at Cypress involves the continuing theories on what decisions were made along the stretch of holes at the ocean. During construction and even after completion of much of the golf course, both MacKenzie and Hunter wrote descriptions of the 16th as a par 4. By these accounts, the routing would have been an unusual 35 going out and 38 coming in for a total par 73. The ocean holes were likely to have played a big part in the routing. Except for the locations of tees and slight shifts in green sites, these holes were mostly nonadjustable. All movement had to lead up to them, and the holes that did were far less etched in stone.
Also somewhat a mystery is the March 1926 presentation plan by Barrows that formed a par 73. This play showed the holes playing as follows: Out — 4, 5, 3, 4, 4*, 3*, 4*, 4, 4 = 35; and then In — 5, 5*, 5*, 3*, 4, 3, 4*, 4, 4 = 38. The asterisked pars show where changes were later made in the final layout. The final routing ended up as: Out — 4, 5, 3, 4, 5, 5, 3, 4, 4 = 37; and then In — 5, 4, 4, 4, 4, 3, 3, 4, 4 = 35 — quite opposite that of the presentation plan in terms of the front and back. How is it supposed that such a swing between nines occurred?
Could MacKenzie and Hunter have had plans up their sleeves to adjust the back-to-back par 5s on the front? Or, did they make any effort to change the 17th into a par 5? This latter idea has not been given much attention, but with ample room for a farther seabound tee at No. 17, perhaps less opportunity to cut past the stand of cypress trees at the fairway, and maybe even less clearing along the cliffs, the 17th may well have been Cypress’s answer to the Cape Hole, the popular 18th down the road at Pebble Beach. True, such a hole may have been a marginal par 5 in terms of length, but there is no question that a hole of even 460 yards in this era, especially one with the ocean to the slice side, would be a deciding hole toward the end of the round. One sure to tempt players to try for eagle.
It was well known that MacKenzie, even as late as 1931, was intent on convincing the Club to install an island tee at No. 18 that would lengthen the hole by as much as 50 yards. His design concept at the 18th called for a suspension bridge and was even taken to the engineering stage. This idea was vetoed by Samuel Morse as being too intrusive and possibly dangerous. So, if not at the 18th, then why not a tee way out at the 17th? No bridge would be required at 17.
If the 17th had been made into a par 5 and if the 16th had been made a par 4, the series along the ocean might have been 3, 4, and then 5 — perhaps a better-appearing series, certainly seeming more diverse to anyone looking at the scorecard from afar. Hollins was dead set against the 16th being anything but a stout par 3, and the 14th had been shifted away from the ocean, so the desire to explore a par 5 along the sea at the 17th may have been even stronger."