I believe restraint is a huge factor, but not the sole characteristic that sets the best apart. Sometimes, restraint is not what the mission or assignment is to the selection of which architect gets a job. Yet, even if a job calls for something extraordinary due to target market, type of facility, and intention of which target market the course is to be created for, even then, knowing how to pull back from what is truly over-the-top is a trademark of 'the best'.
Let's look at an example. Whistling Straits is a course the developer humorously says, 'he gave Pete Dye and unlimited budget - and he exceeded it'. One should consider the property that was given. Some say an unremarkable flatish property with a couple of creeks running through it to the typical Lake Michigan sandy-washed stoney beach with a bit of a rise from the beach a few yards in, and then unremarkable topography. The interesting feature being that the land was used in WWII for target practice for Navy dive bombers. So, it was also an environmental clean-up site.
I think it is plausible that a great architect could have taken that land and have done a minimalist routing that would yield a good golf course, with flatish style, and earth work features just enough to give the hole corridors definition, and some slopes and green pads with interesting surrounding hazards, etc. There are any number of models and styles for such from some of the Mac-Raynor repitoire to modern day examples like Rustic Canyon.
But, the mission was given that they wanted the bombastic, and price was no object, and restraint was not the prime goal. So, we got unrestrained, yet arguably great design that can hold big major tournaments, and has the high end wow factor sizzle of the elite resort. The goal was not restraint and Pete wanted the lake to be seen from almost everywhere on the golf course. He still needed all the other elements of talent and to be among the best to conceive the two tier ledges system, and to move that much dirt and get it all approved. So, other factors came into the mission, and restraint wasn't one of them.
One can argue that he could have used some restraint in creating bunkers that are so remote, they don't come into play, even for hot dog vendors at the PGA. I agree. I don't know why he didn't restrain that! But, not many are going to argue that Dye isn't amonge of the best archies and he didn't come up with something, 'one of the best of its kind'.