Mark
He is not fully appreciated. Watson designed many more courses than what is generally known. I've identified 45 designs in California, Minnesota, Illinois, Michigan, Ohio, Colorado, Arizona and New York, including some high profile courses credited to others, like Thousand Island (Raynor), Toledo (Park) and White Bear Yacht (Ross). There is still quite bit of Watson at Interlachen, and he designed Minikahda. He was heavily involved in two of the courses at Olympia Fields. Olympic-Ocean may have been his greatest accomplishment, but unfortunately it fell into the sea.
He is unique in that he was not home-grown professional in Scotland, nor even a good amateur. I'm still trying to figure out how he became a pro, I think his father was involved in clubmaking, and they came over together. To my knowledge he never competed in tournament. His design career stretched from 1898 to 1928, and that covers some pretty dramatic changes.
That is the first I've read of him being associated with the Chicago GC.