I can't some up with a single reason why good architecture requires high levels of difficulty. But, other than TOC, how many "easy" courses are on anyone's top-ten list?
For me, as I've said too often here, there are too damned many hard courses around and not enough interesting courses.
But as far as I can figure out, achieving interesting without too much difficulty must be really, really hard.
OTOH, I think I know what it looks like. Undulating fairways and greens, almost no rough around the greens, "interesting" bunkers, and, most important of all, limited opportunities to pile up penalty strokes.
Like the Old Course, and Brora....
Good players love narrow fairways bordered by lost-ball rough or water (if it's not TOO close) Because for the most part, they view golf as a game of skill. They don't like "good" shots that end up in a bad spot, and they REALLY hate it when they hit a shot exactly as they planned and it doesn't work.
During the Shinnecock debacle some pro, don't remember who, said "I hit perfect lob wedge and it bounced over the green into a bunker."
IMHO, this is pretty much and American thing, though. I was to a Scottish + handicapper about and said that most Americans think golf is a test of skill and most Scots see it as a test of character. He allowed as that was true, and said he'd seen the difference with friends of his.
K
Oh, and re. Joe's question, I think you're right, people don't think about it as much in match play, but no one likes a course that dramatically favors their opponents skillset.
For instance, the course I used to play had a men's match play league and it was one of those courses where a crappy ball striker like me could maneuver it down the rough and then do something amazing by the green.
So one night I chipped in for par and a half on the 14th hole without ever seeing the fairway. I ran into my opponent from that match about 10 years later, and despite having given up the game, he remembered that hole, and was still a little POed about it.
K