Pete Dye has to be up there. It takes a lot of guts to look at what the most renowned name in your profession doing, and then do the opposite.
Charles Blair MacDonald would also be right there at the top. Copying all the of best holes from the British Isles on one course, then naming it "National Golf Links of America"? Pretty bold. Also, from what I've read about the construction of courses like Yale and The Lido, MacDonald had a vision for building golf courses in extreme locations that only a couple of architects (notably Pete Dye) haven't had since.
Finally, going back even earlier, Old Tom Morris should be on any list. It took great courage to build the manmade greens at St. Andrews (along with Allan Robertson) on holes 1, 17, and 18, and he also dared to play with and design for the modern golf ball. Moreover, Old Tom Morris was the first architect to build courses in several different towns, and his work helped spread the game in the British Isles (this is something most people don't think about, because they are focused on how the game spread from the British Isles as opposed to within them).