I have read and re-read this entire topic several times trying to pull my thoughts together on this subject. IMHO... I have decided ALL courses are "replicas" to one degree or another.
I'm convinced you can pick ANY hole on ANY modern course and a "similar" design can be found somewhere on a "classic" course. The surrounding landscape might be different; the hole might feature sand as an obstacle instead of water; one may be by the sea, the other by a mountain. But, the bottom line is that there is nothing new under the sun. Every golden age designer copied features from his home courses and replicated their famous holes here in America. And many, particularly Donald Ross, copied them over and over again.
The genius of a great golf course designer is that he (or she) can see the possibilities that the land offers and bring them to life. I am reminded of the quote by Elbert Hubbard, "The sculptor produces the beautiful statue by chipping away such parts of the marble block as are not needed." The fact that a certain style hole might have existed before on another course is immaterial. If it fits, it fits. If it works, it works. If it pleases the golfing public, it pleases the gofling public. If a course, or a single hole for that matter, is intentionally created in the "style" of a classic because it pleases the designer, the owner, or the paying public then, so be it. Imitation IS the sincerest form of flattery.
As for the true "replica" courses like Tour 18... golf is a great game, but it is also a business. These courses are simply a novelty item that provide their owners a "hook" that works in the marketplace. I say more power to them. What's the concern? That someone might not visit St Andrews because he's already played a copy of a couple of holes in Texas? Get real. And what's wrong with a theme course. Are you afraid that someone might make a few bucks by evoking the name of a long dead designer? If the public respects the work and enjoys the course they will pay to play it... if not, it will fade away. That is the way it has always been, even in the days of Old Tom.
You classical purists remind me of the conservative religious groups we have here in the south. They think they have all the answers, too. If you want to get to Heaven it's their way, or the highway. And, don't even think of changing one word in the King James version of the Bible or you will be struck blind. Sound familiar? If some of you guys had been making decisions in the days of the "classic" designers many of the courses you so revere wouldn't exist because they are nothing more than replicas of the famous holes and courses their designers treasured and respected.
Bottom line... the world is better place every time a new golf course is built. Just keep 'em coming!