Ron Forse makes the point in his lectures on restoration that the classical courses were built with match play in mind and that modern courses are built with metal play in mind. He notes that Pete Dye brought this back.My notes also contain:
The three elements of a good golf course-
1)Strategy(often lacking in modern courses-swing away vs thinking)
2)Variety(modern courses often fail-features are not random)
3)Naturalness
Classic Courses are beautiful-Why? Cuts and fills are proportionate.(not equal)Nothing raised on ground.
Classic courses have undulating berms.
Ground rules for Classic Golf Course Restoration and Renovation
1)ROUTING of course uses the lay of the land well to minimise earth work.
2)The Scottish LINKS were the greatest influence on the classic designers.
3)INDIVIDUAL HOLES were designed to complement the other 17 for optimal variety in a round of golf. Within each group of Par(I.e,3's,4's&5's)golf holes reflect different lengths and types of tee and approach shots.For example,some Par 5'sare gambling birdie types while others are true 3-shot holes.(careful-if lengthening course-tees back-holes change)
4)STRATEGY is the paramount concept in the design of an individual hole,not photogenicity or penalty.An alternate, longer and less risky way to the hole is provided in the design for the bogey golfer.
5)PERMANENT GROUND FEATURES dictate design, not trees, (unless an old oak or such,can be used.) Safety is a primary use for trees.Many courses are now going to the expense to remove trees.The lesson is to use trees sparingly.Trees improperly used really hurt the design intent.
(Tree line-200 feet-clear cutting)
(You need-110 feet-fairway width)
6)BUNKERS are used to make the game interesting,not necessarily to penalize.Strategy is the driving force behind bunker placement.
7)BUNKERS often designed by Architects were DEEP,to present a true risk to gain a true reward,i.e. for true and strategic impact.Shallow bunkers often do not present enough risk.It is best when a tension is impressed on the player's mind as he strategizes and weighs options with the attendant risks and rewards. i.e.shot value.
On the other hand, DIFFERENT BUNKER DEPTHS are often enployed for variety.
9)MOUNDS and other topographic features have natural appearance with undulating horizons and forms that constantly change. Unpredictably,rather than a mechanical look prevails.
10)GREENS are often SQUARED UP, especially along the front.
11)GREENCOUNTOURS seperate cupping areas to reward a well played shot.
12)FAIRWAYS ARE WIDE (often 150 feet i.e. Pinehurst).
These basic, over-arching principles must guide any restoration or interpretive renovation work.These give an understanding of the original architect's intent and approach.
I hope Ron's lecture helps with your understanding of the term "Classic Course."