I've never heard this term before, so I can't be accused of trying to achieve the term itself, but you have to be careful how you're applying it here. Ross's routings are no less forced upon the land than Bill Coore's, or any other minimalist's; and MacKenzie's bunkers are far from careless or thoughtless.
I do agree that this characteristic is what makes a lot of older courses (and especially links courses) great, but I don't know that you will find a lot of it in modern design, or even in Golden Age architecture ... maybe Ross' chocolate drops count.
I think that story MacKenzie told about natural contouring of greens may apply -- finding the biggest fool in the village, and telling him to make them flat. The trouble with modern architecture's lack of "sprezzatura" may be that we are expected to spend so much time on each project nowadays, to keep coming back, to make sure there are no "errors". We find all the most talented people and they all try so hard.