If someone was to design only one course, then that person should be able to escape the criticism of being repetitious. Unless, there was a lot of repetition within a single course, and then it becomes a one hit blunder?
Seriously though, I think there are a lot of posters on here who, given a sufficient budget and a good piece of land, could come up with a good course. And one of the reasons I think that is they have seen a lot of great holes and could fit them together. Original work is another matter and I think that is where the true test of architecture comes in.
Anyone, literally anyone, can take a great picture, but it takes a true photographer to take a lot of great pictures. I think the same applies to one hit wonders. Anyone can build a great hole, but it takes talent to build a good course, and tremendous talent to build a lot of great courses.