Pat,
Two things:
First, I was interested to see Andy North describe the slope as "severe". I remember having that impression, but it has been five years since I've been to Augusta and I didn't fully trust my memory.
Second, I think the 15th hole has gone through changes that may have influenced perceptions about its difficulty. 30-40 years ago the third shot was always described as very difficult for Masters level players. Then, within the past 10 years or so, we haven't heard this point very much during the Masters telecast.
But, now we have the NY Times article which is a throwback to the 1980s.
Seems like the golf ball technology changed leading far more players to go for the green than 30-40 years ago, essentially minimizing player exposure to the challenge of the third shot. But, then the trees are planted making it more difficult to just bomb away and assume you will be in position to go for the green in two. So, here we are again with the pros taking about how tough the third shot is.