Phil:
The one time I attended The Masters, in 1983, it was extremely wet -- the only year they ever had to finish on a Monday. Lots of players had trouble with spinning the ball back off the greens into trouble; only the guys who were really good ball strikers could figure out how to handle those conditions. [Ballesteros won.]
I think the best courses are generally still the best courses in bad weather -- but not as good as when they dry out.