Perhaps the third time is the charm...perhaps metaphor or some other literary trick served only to cloud the meaning...
Signature holes do have two interpretations. The lesser, according to me, would be the one to which marketing machines subscribe. We need to tell our potential clients which hole is the best, for whatever reason. They should crave the opportunity to play it and, if necessary, anticipation of it will obscure the mediocrity of the remaining holes.
The greater interpretation, according to me, is the signature or stamp or seal of approval of the architect. This greater interpretation is made by those wise or educated in golf course architecture (the minimum would be involvement in a site like this one.) It allows you to differentiate between a Rulewich and a Travis, a Finger and a Ross, a Fazio and a MacKenzie.
To be sure, at least I (and I suspect others) could be fooled by someone with enough zeal to fool us, into thinking that one is another, or vice-versa. That's not the point, but I congratulate you ahead of time.
The point is this: could you have 18 RTJSR, Muirhead, or Hills signature holes on a course? I say not, as they and others tended toward the flamboyant and too much flamboyancy eliminates the uniqueness of one signature hole that the marketers crave.
In contrast, a more subtle, nuanced architect will achieve greater balance, even when a portion of the land lends itself to greater or lesser success. Ergo, an S&N architect arrives at 18 signature holes whereas a flamboyant one cannot and will not.
The template brigade would be left out of this equation, as its purpose (Banks, Raynor, MacDonald) was to replicate tried-and-true equations over varying pieces of land.
Now I'm interested to read responses to this diatribe.