In his review of Huntingdon Valley, Ran wrote, "For no good reason, William Flynn has become the most underrated architect in the game’s history. Now that it has become fashionable to sing the praises of Seth Raynor (and well-deserved the praises are), Flynn is mysteriously overlooked in discussions of the noteworthy designers."
After playing and examining HV, Rolling Green, Lancaster, Lehigh, and others, I think I agree that William Flynn is indeed the most underrated golf course architect of all time.
I'm curious to see who you think would be the most underrated GCAs of all time.