No reason at all why NBWL can't be the greatest course in the world for some people. I have only ever had the pleasure of playing there once, in driving snow in early April 2013, and to be frank that wasn't the best context for a proper appreciation. But what I did see I really enjoyed. But isn't Bernard Darwin's celebrated formulation re Aberdovey as 'the course my soul loves best in all the world' perhaps a better and more appropriate evaluation, in this context, given our general GCA aversion to defining anything as categorically 'the best' (regardless of season, weather, condition, company, our own form etc etc).
Maybe an alternative rhetorical question is where, today, would I most like to play golf anywhere in the world? For me, personally, the answer more than often not remains Harlech, which is I fully appreciate a minority view, but over the years I have enjoyed myself more there than anywhere else, and expect so do to going forward. But any course, like both NWBL and Harlech, that provides both a great test of golf and is also a great place for a game of golf with friends, is doing something fundamentally pretty right.
To strike a more heretical note, for me personally the second best course in the Lothians is Luffness New, which I would have expected to receive a bit more GCA love than seems its ration. As of 4pm this bright and blustery Wednesday afternoon, a magic carpet that could transport me to the first tee at Luffness, ready to play and reinforced by the largest measure of club claret in Christendom, would be immensely welcome.